D. A. Carson notes that Peter needs not only to receive Jesus’ forgiveness but also a reinstatement of sorts among the disciples (16c). (Carson, PNTC, John, 676)
Jesus finds us as he found Peter: shamed and in need of forgiveness. But he doesn’t leave us as he found us. This is different from the common saying: “Jesus loves me just as I am.” Often people use that expression to mean that they can be redeemed by Christ and still live as they did when they were unbelievers. But Jesus didn’t save you so that you can remain as a sinner wallowing in the mire and muck of your sin. Jesus loves you too much and has paid too high a price to leave you as he found you.
When we say, “Come just as you are,” what we mean is that you can’t clean yourself up and then come to Christ. You will never be clean enough apart from the atoning work of Christ. And if you could clean yourself up enough to make yourself acceptable to God, why would you need Christ anyway? You come as you are but Jesus will not leave you as you are; he will transform you and make you who you are supposed to be in him.
This reminds us of a recurring theme in John. Jesus does not see his disciples as they are: weak, impotent, shamed, useless to the Kingdom of God; instead, he sees them as they will be, as he will make them through his Word and Spirit: bold, courageous, mighty. He makes them essential to the work of building up the Kingdom of God. He will do the same for you.