Again, what does it mean to "live under the new covenant,"

Again, what does it mean to "live under the new covenant," or the promise of God?

All God's promises were made to the "Seed" (singular), which is Christ (Gal. 3:16), and the only way we come into the picture is "in Christ." But thank God, that's our "way."

Christ was known as "the son of David" not only through physical ancestry, but because in His incarnation He "lived" in David's psalms. As the leadership of God's true church condemned Jesus, so the divinely appointed leadership of His true church in the days of King Saul condemned David. Saul was "the anointed of the Lord," and David's agony was not only the physical exertion of constantly fleeing from Saul but wrestling with the greater temptation to doubt that God had truly anointed him to be king of Israel, when "the anointed of the Lord" condemned him. He had to overcome, to believe that God would take care of him.

Thus we have David's psalms written during his exile (57, 59. for example); repeatedly, the future king begins by wrestling with fear (old covenant-inspired!), and before the end of the psalm he erupts in new covenant joy of believing that the LORD will not forsake but vindicate him.

A millennium later the Son of God, sent "in the likeness of sinful flesh, and for sin, condemned sin in the flesh" (Rom. 8:3) which He had taken upon Himself, wrestles with the same temptation. Again He is "tempted in all points like as we are, yet without sin" (Heb. 4:15), triumphing again over our old covenant fears, emerging day by day into new covenant sunlight (cf. Isa. 50:4, 5). This goes on continually in His earthly life until the greatest temptation of all to old covenant unbelief as He hangs on His cross in the darkness crying, "My God, why have You forsaken Me?" And there on the cross He wrestles His way through the darkness into the sunlight of new covenant faith, crying out joyously as His heart was already bleeding to death, "You who fear the Lord, praise Him! ... He has not despised nor abhorred the affliction of the afflicted [Me!], nor has He hidden His face from Him [Me!], ... He heard"! (Psalm 22:23, 24).

Jesus has taught us how to live under the new covenant.