Matthew uses Jesus' words in 5:17-20 as a thesis statement for the whole of 5:21-48 which follows. Jesus essentially says, "Look, if you thought the law was tough, wait till you see this. If you really want to be my disciples, give me your hearts without reservation" (see 5:17).

This passage seems to suggest that an uncommitted Christian is not a Christian at all (see 5:20). Like other Jewish teachers, Jesus demanded whole obedience to the Scriptures (5:18-19); unlike most of his contemporaries, however, he was not satisfied with the performance of scribes and Pharisees, observing that this law observance fell short even of the demands of salvation (5:20). After grabbing his hearers' attention with such a statement, Jesus goes on to define God's law not simply in terms of how people behave but in terms of who they really are (5:21-48).