But let him ask in faith
Not only in the faith of the divine Being that God is; but in the faith of the promises he has made; and in the faith of his power and faithfulness to perform them; and in the faith of this, that whatever is asked, according to the will of God, and is for his glory, and his people's good, shall be given.
Nothing wavering;
about the thing asked for, whether it is right or no to ask for it; for that should be settled before it is asked for; nor about the power of God to do it; nor about his will, in things he has declared he will do; nor about his faithfulness to his promises; nor at all questioning but what is proper, suitable, and convenient, will be given in God's own time and way.
For he that wavereth is like a wave of the sea driven with the wind
and tossed;
he is troubled, restless, unquiet, and impatient; and he is fickle, inconstant, unstable, and unsettled; and is easily carried away with every wind of doctrine, temptation, and lust.