Narrow gates, false prophets, and being denied by the Lord all stem from the same thing: the religion of "You." Craig and Troy work through some hard sayings in Jesus' sermon.
Luther saw that God demands not that we become perfectly righteous like God but that we simply receive the gift of righteousness; a gift that actually makes us worthy.
Good works do not give us a righteousness that exceeds that of the scribes and Pharisees. Rather, good works result from righteousness given by the good work of the Righteous One on the cross.