Dated between a.d 60 and 150 the Didache is an early Christian manual on how to do church, covering baptism, communion, righteous living, and other practical topics. It is one of the earliest Christian documents ever written apart from those which are in the New Testament.
Nor should you pray like the hypocrites. Instead, pray like this, just as the Lord commanded in his Gospel: “Our Father in heaven, hallowed be your name, your kingdom come, your will be done on earth as it is in heaven…”
Just as this broken bread was scattered upon the mountains and then was gathered together and became one, so may your church be gathered together from the ends of the earth into your kingdom; for yours is the glory and the power through Jesus Christ forever.
5 Remember your church, Lord, to deliver it from all evil and to make it perfect in your love; and from the four winds gather the church that has been sanctified into your kingdom, which you have prepared for it; for yours is the power and glory forever. 6 May grace come, and may this world pass away. Hosanna to the God of David. If anyone is holy, let him come; if anyone is not, let him repent. Maranatha! Amen.
6 And then there will appear the signs of the truth: first the sign of an opening in heaven, then the sign of the sound of a trumpet, and third, the resurrection of the dead—7 but not of all; rather, as it has been said, “The Lord will come, and all his saints with him.” 8 Then the world will see the Lord coming upon the clouds of heaven.
The author(s) of the Didache believed the kingdom was in the future. Some Christians today say that although Jesus prayed for God’s kingdom to come, it arrived on the day of Pentecost. However, the Didache goes against such an idea, since they were still praying for the kingdom to come. We see a hope that God will gather together the church into God’s kingdom. At first this may not seem unusual until we realize how corporate the language is. Instead of individuals going to heaven at death, the Didache instructs us to pray that God would gather all of his church into his kingdom. This is an event that happens once at the end of our age. Lastly, this document teaches that Jesus is coming back to this earth with his saints. The goal is not to depart and join Jesus in heaven, but to meet him (presumably in the air on his way down cf. 1 Thessalonians 4.17) and escort him to his destination on earth.