He was talking to those people preparing them for persecution during that time he was talking to that generation. We can still take those principles today and apply them to our lives as we are being persecuted still.
Psalm 37:1-9 KJV Fret not thyself because of evildoers, neither be thou envious against the workers of iniquity. [2] For they shall soon be cut down like the grass, and wither as the green herb. [3] Trust in the Lord, and do good; so shalt thou dwell in the land, and verily thou shalt be fed. [4] Delight thyself also in the Lord ; and he shall give thee the desires of thine heart. [5] Commit thy way unto the Lord ; trust also in him; and he shall bring it to pass. [6] And he shall bring forth thy righteousness as the light, and thy judgment as the noonday. [7] Rest in the Lord, and wait patiently for him: fret not thyself because of him who prospereth in his way, because of the man who bringeth wicked devices to pass. [8] Cease from anger, and forsake wrath: fret not thyself in any wise to do evil. [9] For evildoers shall be cut off: but those that wait upon the Lord, they shall inherit the earth.
