The command to “cease to do evil” (Isa. 1:16), and to “sin no more” (Jn. 8:11), implies that all sin is volitional. It implies that sin is not some involuntary substance dwelling inside of you which you cannot get rid of. Therefore, you don’t need a new body or a new substance to be free from sin.
You can have a pure and perfect heart or be morally perfect in this life, even while you have a fallen and corrupted body or are physically imperfect. This is evident since the Bible described certain men as being perfect in heart in this life, even while existing in their corrupted, depraved, or fallen flesh (1 Kin. 6:61; 11:4; 15:3; 15:14; 20:3; 1 Chron. 12:38; 28:9; 29:9; 29:19; 15:17; 16:9; 19:9; 25:2; Job 1:1, 8; Ps. 102:1; Isa. 38:3). “And the Lord said unto Satan, hast thou considered my servant Job, that there is none like him in the earth, a perfect and upright man, one that feareth God, and escheweth evil? (Job 1:8). “And said, Remember now, O Lord, I beseech thee, how I have walked before thee in truth and with a perfect heart, and have done that which is good in thy sight” (Isa. 38:3).
Clearly, you can be morally perfect, or completely obedient to God, even while you’re physically depraved. Your heart can be right with God, in obeying all the moral knowledge that you have, even while your body does not sustain perfect health. Though your flesh is corruptible (just as Jesus’ was, but without sin), your moral character does not have to be. Your will can obey all the moral knowledge of your mind, thus creating a perfect moral character, even while your body or flesh is fallen and depraved, or even while you are physically imperfect.
The distinction between the moral and the physical must be kept in our minds. We must differentiate between moral depravity (Rom. 3:23), and physical depravity (1 Cor. 15:22-23). And we must distinguish between moral perfection (1 Kin. 8:61; Php. 3:15), and physical perfection (1 Cor. 15:42; Php. 3:11-12).