You only stated Romans 8.13, yet to understand 13, you gotta start with vs 12 then go to vs 17:
[SUP]12 [/SUP]So then, brethren, we are under obligation, not to the flesh,
to live according to the flesh— [SUP]13 [/SUP]
for if you are living according to the flesh, you [SUP][f][/SUP]must die; but if by the Spirit you are putting to death the deeds of the body, you will live. [SUP]14 [/SUP]For all who are being led by the Spirit of God, these are sons of God. [SUP]15 [/SUP]For you have not received a spirit of slavery [SUP][
g][/SUP]leading to fear again, but you have received [SUP][
h][/SUP]a spirit of adoption as sons by which we cry out, “Abba! Father!” [SUP]16 [/SUP]The Spirit Himself testifies with our spirit that we are children of God, [SUP]17 [/SUP]and if children, heirs also, heirs of God and fellow heirs with Christ, if indeed we suffer with
Him so that we may also be glorified with
Him.
You took it completely out of context to the discussion.