It is telling what the Bible teaches about the present spirit and walk of them penning God's words. They are holy men of God when doing so.One thing at a time.
Your above comment is very telling--as it is not even biblical.
Not double minded sinners 'sharing' their current personal issues.
Paul no doubt did experience a measure of double heartedness in life as a Christian.Paul was indeed acting within the service and "use for the Master" when he wrote of his struggles and not doing what he willed to do but do what he willed not to do.
The point of the Bible story, is proof that Paul was not always a double minded Christian sinner, like some double minded Christians make him out to be, so they can justify their double minded Christian sinning for life.
Romans 7 is not a road map for Christian living, but an empathetic word from the Lord Jesus with warning to repent.
For in that he himself hath suffered being tempted, he is able to succour them that are tempted.
However, in James 4 the empathy of Lord is not there, but just the commandment that God gives all ungodly sinners to repent.
Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your hearts, ye double minded.
As in Romans 2:
And thinkest thou this, O man, that judgest them which do such things, and doest the same, that thou shalt escape the judgment of God?
Or despisest thou the riches of his goodness and forbearance and longsuffering; not knowing that the goodness of God leadeth thee to repentance?