The following is an excerpt from
The MacArthur New Testament Commentary on Matthew 18.
See that you do not despise one of these little ones for I say to you, that their angels in heaven continually behold the face of My Father who is in heaven. (18:10)
The expression I say to you is emphatic, pointing up the importance of what the Lord is about to say The idea is, “With all My authority I solemnly affirm to you.” He then gives the first compelling reason Christians should never despise other Christians: their relation to their angels in heaven.
The writer of Hebrews explains that the holy, elect angels are “all ministering spirits, sent out to render service for the sake of those who will inherit salvation” (Heb. 1:14). Their purpose is to serve God by attending to the care of His people. These angels in heaven live in the very presence of God, where they wait attentively for His commands to serve the people of His love. “They continually behold the face of My Father who is in heaven,” Jesus said. The implication is that the holy angels never take their eyes off God, lest they miss some direction from Him regarding a task they are to perform on behalf of a believer.
Neither of these texts, however-nor any other Scripture-teaches the idea of an individual guardian angel for every believer, as Jewish tradition in Jesus’ day taught and as many people still believe and teach. When Peter knocked at the door of Mary’s house after he was miraculously released from prison, a servant girl named Rhoda answered. Upon seeing Peter she was so overjoyed she forgot to open the gate. When she reported his presence to the believers gathered inside, it was probably the notion of individual guardian angels that was behind their insistence that she had only seen “Peter’s angel” (Acts 12:12–15). But that superstitious belief is merely reflected in this text; it is neither taught nor substantiated here or anywhere else in Scripture.
In Matthew 18:10 Jesus speaks of believers and their angels in a collective sense. These angels, whether a distinct group or the whole body of holy angels, are responsible for the care of God’s little ones, those who believe in His Son (v. 6). It is in part because of these angels who live in the presence of the Father who is in heaven that believers are warned not to despise one another.
The fact that Almighty God is so concerned about the care of His beloved children that He has hosts of angels in His presence ready to be dispatched to their aid demonstrates dearly how valuable believers are and how unthinkably wicked it is to look with disdain on someone whom God so highly prizes.
As indicated by brackets in the nasb text, verse 11 (For the Son of Man has come to save that which was lost) is not found in the best early manuscripts of this gospel. The almost identical phrase, however, is in Luke 19:10, where “seek and” is added before to save. Because there is no question about the authenticity of the Luke text, there is no question that Matthew 18:11 teaches a genuinely scriptural truth. The phrase was probably picked up from Luke by a well-meaning copyist and added to Matthew. But because it is not a part of Matthew’s original gospel, it will not be discussed here.