James 1:5-8
5 If any of you lacks wisdom, you should ask God, who gives generously to all without finding fault, and it will be given to you.6 But when you ask, you must believe and not doubt, because the one who doubts is like a wave of the sea, blown and tossed by the wind.7 That person should not expect to receive anything from the Lord.8 Such a person is double-minded and unstable in all they do.
_______________________________

There is a difference between doubt and unbelief. Faith is on one end of the spectrum and Unbelief is on the other end. Between these two extremes is doubt – which produces wavering, tossed back and forth. Therefore, even “believers” can be doubters but this passage exhorts us to “not doubt” – indicating it is a choice we can make.

But note, while it is appropriate to apply this passage to believing God in many areas, in context it is specifically saying when we ask for wisdom we must believe God will give it and not doubt.

In my experience that is because often when we ask for wisdom and receive it we don’t realize we have received it. Often the “wisdom from God” comes naturally, and often does not seem so wise. God’s counsel often seems very natural, normal, common sense.

In the past, when I have prayed for wisdom I expected some amazing insight that had never been thought before. Usually, however, His wisdom was common sense, in accordance with Scripture I was familiar with. There is a tendency then to doubt we received anything – “what’ so wise about that?” But when we ask, we must believe that we have received and move out in accordance with what we understand to be God’s will, way and timing, even if it doesn’t seem wise or profound.
________________________
James 3:17
But the wisdom that comes from heaven is first of all pure; then peace-loving, considerate, submissive, full of mercy and good fruit, impartial and sincere.