Passages such as Mat. 5:39 provided a contraposition to certain lines of
reasoning within conteporary First Century Jewish society. First, Jesus'
teaching here represents a position of faith in God. One does not take his
own revenge but trusts God to right all wrongs and to reward those who
believe in Him (Cf. Rom. 8:28-39). Second, it repudiates that "zeal of the
wrong kind, as practiced by the Zealots" (Martin Hengel, _The Zealots_, pp.
225f. n. 402). Third, it serves to distinguish the Messianic movement
centered in Jesus from those that based their pretentions and their hopes on
guerilla military might and retaliatory action.
How we put such teachings of Jesus as this one into practice will depend
on whether we see Him as only a man of His time or as Lord of all the ages.
If the latter, as I believe, in Mat. 5:38-9, we have counsel on how to deal
with situations in which we have been hurt or wronged. This passage amounts
to the Lord's word that we don't need to take on the burden of righting the
wrong ourselves. And, although it is not specifically enunciated, the
implication is present that God is mighty enough to make all things work for
good to those who trust in Him.
David L. Moore