But let him ask in faith without any doubting, for the one who doubts is like the surf of the sea driven and tossed by the wind. For let not that man expect that he will receive anything from the Lord, being a double-minded man, unstable in all his ways. James 1:6-8
When you ask, do it in what you are persuaded, not going back and forth in your convictions. James compares this double minded conduct with the ocean's waves which are driven and moved by an outside force. Otherwise, don't expect anything, because you have two different thought processes.
Recently, I had been praying for someone to have a mind change concerning something they were doing. One way that I have been double-minded in my thinking is that when I finish praying, I tend to think, "Well, if God doesn't answer within a certain time, then I will talk to the person about my desire for their change".
This type thinking puts me in the category of the 'double-minded' man. I ask God, believing He can do it, and then get off my knees and think, "how can I accomplish this".
"…unstable in all his ways"
The instability then moves to other areas of my life, my job, relationships, etc. I tend to ask God for something, believing Him to accomplish His will and then I try to manipulate the circumstances or grumble if it didn't go the way I wanted.
The double-minded man, who is unstable in his thinking and conduct, who wishes to change, needs only look to James 4:8 where he says, "purify your hearts minds you double-minded". This indicates that the one who has these "double-minded" behaviors need only meditate on the Word. This is the process of "purifying the heart".
James says, "but let him ask in faith...". Doubting leads to double-mindedness. Faith is the opposite of doubting. We know that "faith comes by hearing and hearing by the Word of God". So as we build our faith through the Word, it opposes and dispels doubting and double-minded thoughts and conduct.