6. ask in faith--that is, the persuasion that God can and will give. James begins and ends with faith. In the middle of the Epistle he removes the hindrances to faith and shows its true character [BENGEL].
      wavering--between belief and unbelief. Compare the case of the Israelites, who seemed to partly believe in God's power, but leaned more to unbelief by "limiting" it. On the other hand, compare Ac 10:20; Ro 4:20 ("staggered not . . . through unbelief," literally, as here, "wavered not"); 1Ti 2:8.
      like a wave of the sea-- Isa 57:20; Eph 4:14, where the same Greek word occurs for "tossed to and fro," as is here translated, "driven with the wind."
      driven with the wind--from without.
      tossed--from within, by its own instability [BENGEL]. At one time cast on the shore of faith and hope, at another rolled back into the abyss of unbelief; at one time raised to the height of worldly pride, at another tossed in the sands of despair and affliction [WIESINGER].

JFB.