John 14:27, “My peace I leave with you; My peace I give to you. Not as the world gives do I give to you. Let not your hearts be troubled, neither let them be afraid.”
People think Jesus came for world peace. These people do not know Jesus. He Himself says He came not to bring peace, but a sword to divide the world, even within the family (Matthew 10:34-39; Luke 12:49-53). What kind of peace is He talking of here, then? Obviously, not as the world gives. So then, what? First, consider whom He is talking to in the context. He is talking to the disciples after having celebrated the Passover (13:1ff). So then, Jesus is talking to believers here. What sort of peace does He give believers? Welfare and security? No, those are the ways of the world.
Just before this, He promised the Holy Spirit to His disciples when He goes to the Father (14:26). So, we must jump to Acts, which begins with this promise He made to the disciples (1:4-5), then He ascends to be with the Father (1:6-11), reminding them again of the Holy Spirit to come (v. 8). Then, on Pentecost, the Holy Spirit descends upon them all as promised and thousands of people begin to miraculously hear them speak in their own languages (Acts 2). It is in this momentous event that Peter preaches in his sermon, “And it shall come to pass that everyone who calls upon the name of the Lord shall be saved” (2:21). The people, wanting to respond in faith, asked what they are to do, to which Peter responded, “Repent and be baptised, every one of you, in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and your children and for all who are far off, everyone whom the Lord our God calls to Himself” (2:38-39).
So then, in Baptism our sins are forgiven and we receive the Holy Spirit, through whom Christ sets us at peace with God, and it is for all, including children as young as infants. For those who are not baptised, then, these are words of Law. For without Christ in the Holy Spirit through Holy Baptism, we are not at peace with God, left in our condemnation. But for we who are baptised, these are gospel words of great comfort, for Christ has set us at peace with God in the Holy Spirit. Therefore, whenever we begin to fear God because of our sin, we can repent and remember the gift of peace given to us in our Baptism.