John 13 :7 " What I am doing you do not understand now, but afterward you will understand"
Much of the Christian life is spent trusting Jesus now and understanding later. Jesus typically doesn't always explain on the front end why He is doing something the way He is doing it. Like Peter, when something looks wrong to us, we are tempted to go against the Lord's will. God wants us to trust Him. During those times when we don't understand, we need to remember Jesus' words to Peter, "What I am doing you do not understand now, but afterward you will understand".
Peter had grown used to Jesus doing and saying unpredictable things, but in the context of John 13:7, the way Peter saw it, Jesus washing the disciples feet was just plain wrong. He believed Jesus was the last person in the room who should be washing feet, that was a house servant's job, a non-Jew. People traveled in sandals, their feet were smelly, dirty and came in contact with things the law declared unclean.
Here's the twist. Under the law the unclean makes the clean, unclean. But under grace, the clean makes the unclean, clean. Jesus washed the disciples feet, when it should have been Peter down washing the feet of Jesus. It looked like it was all backwards. Peter didn't understand in the now, but he would later.
Today you may not understand what God is doing in your life, but trust Him, you'll understand later. Follow the example in His Word, listen to that still small voice that says "This is the way, walk ye in it" (Isaiah 30:21). Remember this simple truth, God is good, all the time. When your down to nothing, God is up to something! Something good.