John Chrysostom
Catena Aurea · Lukasevangelium 17
And the apostles said unto the Lord, Increase our faith. And the Lord said, If ye had faith as a grain of mustard seed, ye might say unto this sycamine tree, Be thou plucked up by the root, and be thou planted in the sea; and it should obey you.
(Hom. 57. in Matt.) He mentions the mustard seed, because, though small in size, it is mightier in power than all the others. He implies then that the least part of faith can do great things. But though the Apostles did not transplant the mulberry tree, do not thou accuse them; for our Lord said not, You shall transplant, but, You shall be able to transplant. But they did not, because there was no need, seeing that they did greater things. (Hom. 32 in 1 ad Cor. c. 13:2.). But some one will ask, How does Christ say, that it is the least part of faith which can transplant a mulberry tree or a mountain, whereas Paul says that it is all faith which moves mountains? We must then answer, that the Apostle imputes the moving of mountains to all faith, not as though only the whole of faith could do this, but because this seemed a great thing to carnal men on account of the vastness of the body.