From this it follows that one who prays aright never doubts that his prayer is surely acceptable and heard, although the very thing for which he prays be not given him. For we are to lay our need before God in prayer, but not prescribe to Him a measure, manner, time or place; but if He wills to give it to us better or in another way than we think, we are to leave it to Him; for frequently we do not know what we pray, as St. Paul says, Romans viii; and God works and gives above all that we understand, as he says, Ephesians iii, so that there be no doubt that the prayer is acceptable and heard, and we yet leave to God the time, place, measure and limit; He will surely do what is right. They are the true worshipers, who worship God in spirit and in truth. For they who believe not that they will be heard, sin upon the left hand against this Commandment, and go far astray with their unbelief. But they who set a limit for Him, sin upon the other side, and come too close with their tempting of God. So He has forbidden both, that we should err from His Commandment neither to the left nor to the right, that is, neither with unbelief nor with tempting, but with simple faith remain on the straight road, trusting Him, and yet setting Him no bounds. VI. Thus we see that this Commandment, like the Second, is to be nothing else than a doing and keeping of the First Commandment, that is, of faith, trust, confidence, hope and love to God, so that in all the Commandments the First may be the captain, and faith the chief work and the life of all other works, without which, as was said, they cannot be good. But if you say: "What if I cannot believe that my prayer is heard and accepted?" I answer: For this very reason faith, prayer and all other good works are commanded, that you shall know what you can and what you cannot do. And when you find that you cannot so believe and do, then you are humbly to confess it to God, and so begin with a weak spark of faith and daily strengthen it more and more by exercising it in all your living and doing. For as touching infirmity of faith (that is, of the First and highest Commandment), there is no one on earth who does not have his good share of it. For even the holy Apostles in the Gospel, and especially St. Peter, were weak in faith, so that they also prayed Christ and said: "Lord, increase our faith "; and He very frequently rebukes them because they have so little faith.