'Within' in the Bible

For I know that nothing good lives in me, that is, in my flesh [my human nature, my worldliness—my sinful capacity]. For the willingness [to do good] is present in me, but the doing of good is not.

But if I am doing the very thing I do not want to do, I am no longer the one doing it [that is, it is not me that acts], but the sin [nature] which lives in me.

However, you are not [living] in the flesh [controlled by the sinful nature] but in the Spirit, if in fact the Spirit of God lives in you [directing and guiding you]. But if anyone does not have the Spirit of Christ, he does not belong to Him [and is not a child of God].