How does God’s kingdom come? “God’s kingdom comes when our heavenly Father gives us His Holy Spirit, so that by His grace we believe His holy Word and lead godly lives here in time and there in eternity” (SC, The Second Petition).
As Luther continues in the Large Catechism, “For the coming of God’s kingdom to us happens in two ways: (a) here in time through the Word and faith [Matthew 13]; and (b) in eternity forever through revelation [Luke 19:11; 1 Peter 1:4-5]. Now we pray for both these things. We pray that the kingdom may come to those who are not yet in it, and, by daily growth that it may come to us who have received it, both now and hereafter in eternal life” (LC III, 53).
Therefore, the kingdom of God has already come to you in your Baptism, for therein you have received the forgiveness of sins and the gift of the Holy Spirit (Acts 2:38). Many teach God’s kingdom is something we have to find somewhere out there, or even that you find it within yourself. Yet they have this backwards. Rather than looking to yourself for God’s kingdom, God’s kingdom comes to you whenever you receive His Word and receive His Sacraments since these give you forgiveness of sins and faith. His kingdom, therefore, comes to you in the Divine Service every time you walk through its gates of the sanctuary. We like to hang pieces of God’s Word like motivational quotes in our homes and offices, but the Word is more than that. His Word inaugurates His kingdom in the here and now—it sows in you the forgiveness of sins.
Furthermore, to reiterate, we also pray in this petition the eschatological prayer, “Come, Lord Jesus.” Just as His kingdom comes to us in His Word and Spirit in the here and now through the corporeal means of His Word and Sacraments, so we pray His kingdom come when Christ our King descends in the clouds in great gory and majesty. Christ will bring His kingdom down to us in the holy city of New Jerusalem, within which is the river of life beside which our Good Shepherd, the Son of David, shall lay us down to drink unto life everlasting (Psalm 23:2). Surely, He is coming soon. Amen. Come, Lord Jesus! (Revelation 22:20).