John Chrysostom
Say with him, David: “How long, O Lord, will You forget me forever? How long will You turn Your face away from me?” (Ps 12:2).
Say it not with the tongue, but first with the heart. Offer also the other supplications of David.
When you have expressed everything, hope in the mercy of God. Hope, and do not doubt.
“But let him ask in faith, with no doubting,” says the Apostle, “for he who doubts is like a wave of the sea, driven and tossed by the wind. Let not that man think that he will receive anything from the Lord. A man of double mind is unstable in all his ways” (Jas 1:6-8).
Therefore hope in His mercy, not doubting at all, and you will surely receive what you ask. Having received it, do not be ungrateful or thankless toward your Benefactor.
Rather, set up a memorial of His benefaction and raise a hymn of thanksgiving to the Lord.