But though men may with preaching be ministers unto God therein; and though a man can, with his own free will, obeying freely the inward inspiration of God, be a weak worker with almighty God therein; yet is the faith indeed the gracious gift of God himself.
For, as St. James saith, “Every good gift and every perfect gift is given from above, descending from the Father of lights.”
Therefore, feeling our faith by many tokens very faint, let us pray to him who giveth it to us, that it may please him to help and increase it.
And let us first say with him in the gospel, “I believe, good Lord, but help thou the lack of my belief.” And afterwards, let us pray with the apostles, “Lord, increase our faith.”
And finally, let us consider, by Christ’s saying unto them, that, if we would not suffer the strength and fervour of our faith to wax lukewarm—or rather key-cold—and lose its vigour by scattering our minds abroad about so many trifling things that we very seldom think of the matters of our faith, we should withdraw our thought from the respect and regard of all worldly fantasies, and so gather our faith together into a little narrow room.
And like the little grain of mustard seed, which is by nature hot, we should set it in the garden of our soul, all weeds being pulled out for the better feeding of our faith.
Then shall it grow, and so spread up in height that the birds—that is, the holy angels of heaven—shall breed in our soul, and bring forth virtues in the branches of our faith.
And then, with the faithful trust that through the true belief of God’s word we shall put in his promise, we shall be well able to command a great mountain of tribulation to void from the place where it stood in our heart, whereas with a very feeble faith and faint, we shall be scantly able to remove a little hillock.
Thomas More (1478-1535): Dialogue of Comfort Against Tribulation 1, 2.