“A glass can only spill what it contains.” - mewithoutyou
That’s not bad insight into life. We often hear the phrase, “garbage in, garbage out,” but that’s true of good things as well. Jesus taught this clearly:
"The good man out of the good treasure of his heart brings forth what is good; and the evil man out of the evil treasure brings forth what is evil; for his mouth speaks from that which fills his heart.” (Luke 6:45)
You don’t have to be a Christian to recognize this. What we pour into our lives is what will eventually pour out of it in some way. It’s one reason people are increasingly talking about the power of entertainment. There are ways to filter it – there’s a lot to be said about learning how to read, listen and watch as a Christian who listens and sees through the eyes and ears of Jesus – but in some fashion, what comes in will come out.
- CNN’s Health section online featured an article entitled “Should Smoking Trigger an R rating?” The author noted, “For every 500 smoking scenes a child saw in PG-13 movies, his or her likelihood of trying cigarettes increased by 49%.” 
- The Official Journal of the American Academy of Pediatrics reported: “Youths [12-17 years old who viewed sexual content on TV] in the 90th percentile of TV sex viewing had a predicted probability of intercourse initiation that was approximately double that of youths in the 10th percentile... Exposure to TV that included only talk about sex was associated with the same risks...”
What we dwell on matters. There is a reason Paul wrote to the Philippian church to focus on things that were good, true, and lovely (Philippians 4:8). The idea of this verse is not that we retreat from anything bad – we would have to live in a bubble – but that we actively pursue a mental and emotional diet made up of predominantly wholesome things.
We all fill our glass with something. The words and actions and attitudes that overflow will reflect the abundance of images and ideas with which we have filled ourselves.
In 2 Corinthians, Paul makes a similar claim: We will become what we see. He uses the analogy of a mirror reflecting, but the idea is the same.
“As we see and reflect the glory of the Lord, we are transfigured by the Spirit of the Lord in ever-increasing splendor into his own image.” (2 Corinthians 3:18)
In essence, we are mirrors that reflect the things at which we look. It’s another way of saying that what flows out of us will be an indicator of what’s been filling us. Before we talk about that more, I need to give a context to this sentence. Paul was talking to the early Christians about the Old Testament Law.
2 Corinthians 3:7-18
7-11 The administration of the Law which was engraved in stone (and which led in fact to spiritual death) was so magnificent that the Israelites were unable to look unflinchingly at Moses’ face, for it was alight with heavenly splendor. Now if the old administration held such heavenly, even though transitory, splendor, can we not see what a much more glorious thing is the new administration of the Spirit of life? If administering a system which ends in condemning men was a splendid task, how infinitely more splendid is administering a system which ends in making men good! And while it is true that the former temporary glory has been completely eclipsed now, we do well to remember that is eclipsed simply because the present permanent plan is such a very much more glorious thing than the old.
12-17 With this hope in our hearts we are quite frank and open in our ministry. We are not like Moses, who veiled his face to prevent the Israelites from seeing its fading glory. But it was their minds really which were blinded, for even today when the old agreement is read to them there is still a veil over their minds—though the veil has actually been lifted by Christ. Yes, alas, even to this day there is still a veil over their hearts when the writings of Moses are read. Yet if they turned to the Lord the veil would disappear, and they would understand how their Scriptures point to Christ. For the Lord to whom they could turn is the spirit of the new agreement, and wherever the Spirit of the Lord is, there is freedom and boldness to proclaim His message.
18 But all of us who are followers of Christ do not have veils on our faces as we see and reflect the glory of the Lord. We are transfigured by the Spirit of the Lord in ever-increasing splendor into his own image.
This passage raises some questions for me: Why is the Law glorious even as it brings death? Why didn’t Moses want them to see his fading glory? How does our being unveiled reflect the glory of the Lord? Since all of this sets the table for verse 18, let’s try to work our way through these questions.
Question #1: How is the Law glorious even though it brings death? Because it was a teacher, a guide to show us how God wants us to live (Romans 15; 1 Corinthians 10). In Galatians 3, Paul wrote,
“Until the time when we were mature enough to respond freely in faith to the living God, we were carefully surrounded and protected by the Mosaic law. The law was like those Greek tutors, with which you are familiar, who escort children to school and protect them from danger or distraction, making sure the children will really get to the place they set out for.” (from The Message’s commentary)
If someone asked, “What does God want me to do?” the Israelites had an answer – 613 answers, in fact. If you had asked a follower of Baal or Molech what their God wanted them to do, they would not have known. They just hoped they were doing the right thing, and if something went wrong, they offered increasingly gruesome sacrifices to appease a mysterious, unknowable, and petty god.
When God gave His Law, He gave something of Himself to His people. Now the will of God could be known. Do this, not that. And if you keep God’s laws, all will be well. We tend to think of the Law as oppressive; the Israelites were grateful that God made himself known. 
You can fill up with God’s law, and if you do that well, good things will overflow….
God’s covenant with His people through the Law of Moses was a conditional covenant; that is, if they kept it, good things would follow. If they didn’t bad things would follow. In some ways obedience to the law was a case study in spiritual cause and effect. That’s an idea we can wrap our minds around because we see it all the time. If we practice, work, use self-discipline – good things happen. We can lose weight or build muscle or make money or hit a softball or graduate or expand our vocabulary or play an instrument or get really good at Wii bowling if we know the rules and try hard enough….
But through his prophets, God warned over and over again: “This is not going to go well.” And it didn’t. The Law made it official that we the people (as seen in the Israelites) are never good enough. God can tell us exactly what He wants us to do, and on our own we will just not do it. On our own, we will inevitably fill ourselves with sin even though we know it will eventually spill out of us and onto others. This is in line with how Paul describes the Law:
“The Law’s purpose was to make obvious to everyone that we are, in ourselves, out of right relationship with God, and therefore to show us the futility of devising some religious system for getting by our own efforts what we can only get by waiting in faith for God to complete his promise. For if any kind of rule-keeping had power to create life in us, we would certainly have gotten it by this time.” (Galatians 3 as written in commentary by The Message)
The law unfortunately answers one of life’s most important questions: Can I be good if I try hard enough? No. It shows you the path of life, and if you stay on that path it will give you life, but… you will wander off of it. 
Question #2: Why didn't Moses want them to see his fading glory?
A glory that is so obvious to everybody – and then fades - is a problem. To all the people watching, apparently Moses was tight with God – and then he wasn’t. I suspect Moses was ashamed of this. Pride makes us hide the parts of our life that shame us. Ron Ritchie writes (I think correctly):
“He realized that as long as he wore the veil, the people showed him respect because they believed that he was still visiting God; otherwise, why would he keep the veil on? But when Moses had not been in the presence of God, the glory of God began to fade underneath the veil…. For Moses the veil represented a false sense of competence, power, authority, glory, and pride. He used it to cover his fear and inadequacy… he sought in his own strength to compensate for the glory that had faded from his face.”
That veil couldn't hide the fact that God’s glory was leaking out through the cracks made by sin. If I understand this passage correctly, Moses couldn’t keep God’s glory, and he was ashamed.
Question #3: Why are we unveiled now?
Because a) we do reflect an ever increasing splendor as we are transformed into the image of Christ, and b) we don’t need to be ashamed when we fail. And perhaps – much to our surprise – even in our failure the glory of God does not fade.
Let’s look more closely at Paul’s claim. He expands the symbolism of hiding behind the veil and writes that followers of Jesus are not meant to hide. They are meant to be on display; in his image with a mirror, they look at the glory of God without shame, and they fully reflect the permanent, ongoing transformative presence of the glory of God in their life.
Our life with Christ is meant to be an ongoing transformation in which we increasingly behold the person and work of Christ, increasingly become changed deep in the core of who we are, and increasingly become filled in such a way that we display the glory of God by His presence and work in our lives.
We remove the veil because it’s not about us. When we have the glory of Christ in our lives, it won’t be because we were awesome. It will be because “we are transfigured by the Spirit of the Lord in ever-increasing splendor into his own image.”
It’s an ongoing process. There’s no way we can escape being sinful and flawed – and that’s okay. After all, who can deny that we still have our ups and downs? We all have times when our reflection wavers, when what spills out of us when we go over the rough roads in life is just not anything we are proud of.
So what is the glory of Christ in our lives that does not fade and should never be hidden? I believe it is the grace and forgiveness that accompanies Christ’s salvation.
The way in which Jesus intends for the world to see his glory is not through our ability to live perfectly. We don’t need to be a crystal clear glass filled with AquaFina. We can be a bottle from the trash filled with muddy rain water and still show God’s glory, because it is through God’s strength in our weakness that His glory is seen.
Let’s revisit last week. I made the point that people will reach conclusions about Jesus by looking at the people of Jesus. That’s daunting. Here’s where we are relieved of the pressure to be perfect.
When we offer Christ to others, we don’t need to wait until we are perfectly clear of mud and junk, and we don’t need to wait to “unveil” who we are until we can present ourselves just right. We aren’t offering us to other people. We are offering a Savior who takes us with all our impurities and makes us new.
We are meant to, with uncovered lives, without shame over the visible gauge of our ability to be good or bad on full display, let God display what real glory is like in the person and work of Jesus.
 For a longer look at the content, context and purpose of the Old Testament law, check out the series at TC Apologetics. Here is a link to the first post in the series: http://tcapologetics.org/old-testament-law-an-introduction/
 “If people in our Christian fellowships today were to announce that they had decided to keep God’s law, we would probably be skeptical and alarmed. We probably would take them aside for counseling and possibly alert other responsible people in the group to keep an eye on them. We would be sure nothing good would come of it. We know that one is not saved by keeping the law and can think of no other reason why one should try to do it. This leaves us caught in a strange inversion of the work of the Judaizing teachers who dogged the footsteps of Paul in New Testament days. As they wanted to add obedience to ritual law to faith in Christ, we want to subtract moral law from faith in Christ. How to combine faith with obedience is surely the essential task of the church as it enters the twenty-first century.” ― Dallas Willard, The Divine Conspiracy: Rediscovering Our Hidden Life In God