The cross is in view. And Jesus is trusting God's plan. Will Peter trust God's plan? Will we trust God's plan?
God's covenant with David is fulfilled through Jesus. God will always do what He says. All the promises of God are fulfilled in Jesus.
The last thing Jesus does with His disciples is to pray for them. What does Jesus pray about? What is on His heart as He is about to leave them?
Jesus' work didn't end at the cross. It continues because Jesus lives. He reminds His disciples in John 16 that He will see them again. We serve a risen Savior.