IT IS A FACT!
Matthew 28:20 (ESV) … “teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.”
Jesus is not only “in the midst” when His people gather together (Matt. 18:20), but He is also present with them as they scatter into the world to witness. Had He remained on earth, Jesus could not have fulfilled this promise. It was when the Spirit came that Jesus could be with His people no matter where they were.
Dr. G. Campbell Morgan told about an experience in his life that involved this statement. Early in his Christian life, Morgan used to visit several ladies once a week to read the Bible to them. When he came to the end of Matthew’s Gospel, Morgan read, “Lo, I am with you always, even unto the end of this age.” He added, “Isn’t that a wonderful promise?” One of the ladies quickly replied, “Young man, that is not a promise—it is a fact!”
There are no conditions for us to meet, or even to believe; for Jesus Christ is with us. Paul discovered this to be true when he was seeking to establish a church in the difficult city of Corinth. Obeying this commission, Paul came to the city (Acts 18:1), won people to Christ and baptized them (Acts 18:8) and taught them the word (Acts 18:11). When the going was tough, Paul had a special visit from the Lord: “Be not afraid … for I am with thee” (Acts 18:9–10).
The phrase “the end of the age” indicates that our Lord has a plan; He is the Lord of history. As the churches follow His leading and obey His Word, they fulfill His purposes in the world. It will all come to a climax one day; meanwhile, we must all be faithful.
 Wiersbe, W. W. (1996). The Bible exposition commentary (Vol. 1, p. 108). Wheaton, IL: Victor Books.