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.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. 57. in Matt.