In John 10:10, Jesus says, "I have come that you may have life and have it abundantly."
What is abundant life, and why does it matter? The word in the Greek has to do with something filled to the brim – like that suitcase you packed for Summer Training that you had to sit on in order to get it closed. It's about having everything you could possibly want or need with no room for anything else. In fact, King David – the great Psalmist – declares that God desires to give us so much that "my cup overflows" (Psalm 23). It's not just packed to the top but literally bursting at the seams. That's what God wants us to have and that's the kind of life that Jesus says he's come to give us.
But so many are satisfied with less than God wants to give us in Christ. You've heard the diagnostic question: "Do you see the glass as half empty or half full?" And we easily begin to think that as long as we see it as half full – as long as our outlook on life is good and optimistic – that everything is fine. The problem is that God doesn't want to fill your glass halfway, regardless of how you look at it, he wants to fill it the brim, to overflowing, so that there isn't any question as to how you should see it. So God keeps pouring out his gifts that satisfy and fill and overflow – through his Word, through Baptism, through Communion, through Confession and Absolution, through the mutual conversation and consolation of your brothers and sisters in Christ – but too many of us don't want those gifts and so we poke holes in the top of our cups so that the blessings God gives us to have abundant life can never reach the top. We reject God's gifts that he says will fill us because we want something different. We want what we want, not what God wants us to want. It's called sin. It's like eating 2 gallons of chocolate chip ice cream for dinner: you know it won't do anything good for you, it even deprives you of getting good stuff from healthy food. But we live in an ice-cream-for-dinner-world when it comes to the Bible and God's gifts to us in Christ.
That's why Christians are called to live it up to the full, to overflowing, in the blessings that God gives us: because, as we live in the fullness of Christ's gifts, the world will see our lives and will long for the kind of life that Christ gives us. They'll look out from their tombs (Ephesians 2:1) and long to live like the living rather than the dead. They'll see that life isn't about simply having a half full or half empty cup, but about having it all the way God intended it. So even the good gifts Christ gives us of the forgiveness of sins, life, and salvation are both for us to experience and for the world to see.
If you aren't experiencing the abundant life, let me encourage you to go to church; hear his Word and receive his gifts and really think about – believe – what Jesus has done for you, and just soak up his gifts. Let God's Word in Christ fill you up (Colossians 3:16) and replace everything else: confess your sins and get rid of them, and live in the Gospel. In so doing, your "light will shine before others, that they may see your good works and give glory to your Father who is in heaven" (Matthew 5:16). That's the abundant life – life lived in Christ and overflowing with his love.