The Messiah had the same flesh as us that tempted him in all ways and yet had no sin. So sin doesn't necessarily remain because of the flesh. Sin remains because we fail the test of temptation.
James 1:12-15
12 Blessed is the man who perseveres under trial, because when he has stood the test, he will receive the crown of life that God has promised to those who love Him.
13 When tempted, no one should say, “God is tempting me.” For God cannot be tempted by evil, nor does He tempt anyone. 14 But each one is tempted when by his own evil desires he is lured away and enticed
15 Then after desire has conceived, it gives birth to sin; and sin, when it is full-grown, gives birth to death
We're expected to mature to eventually withstand the test of temptation to sin like the Messiah did, and we are told to ask freely of all the gifts necessary to do that.
James 1:12-15
12 Blessed is the man who perseveres under trial, because when he has stood the test, he will receive the crown of life that God has promised to those who love Him.
13 When tempted, no one should say, “God is tempting me.” For God cannot be tempted by evil, nor does He tempt anyone. 14 But each one is tempted when by his own evil desires he is lured away and enticed
15 Then after desire has conceived, it gives birth to sin; and sin, when it is full-grown, gives birth to death
We're expected to mature to eventually withstand the test of temptation to sin like the Messiah did, and we are told to ask freely of all the gifts necessary to do that.
23But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members.
24O wretched man that I am! who shall deliver me from the body of this death?