Where two or three are gathered together in my name, I am there in the midst of them.(Matthew 18:20)
Is it not possible for a person to pray or worship or meditate on God's Word alone and feel God's presence? Yes, definitely; yet here, Jesus says that "where two or three are gathered together in his name, he is there in the midst of them." Perhaps, he was pointing to a notion prevalent among the Jews that at least 10 were to be gathered to be a congregation. Not needed, Jesus seemed to imply by his statement.
Ubi tres, ibi Ecclesia (“Where three are, there is a church”) is a well known patristic axiom- (Patristic means-of or relating to the church fathers or their writings; axiom means established or accepted statement)
At any moment of time, any place in the world, where two or three are gathered in Jesus' name, he is in their midst. Christ's omnipresence and omniscience is so very evident in his statement and it provides great comfort to those who believe.
Jesus' promise stays true through the centuries, despite major changes in culture, technology, politics and other factors that tend to change over time.