Theophylact of Ohrid
Catena Aurea · Lukasevangelium 17
Lk 17, Verses 5–6English original
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.
But our Lord told them that they asked well, and that they ought to believe stedfastly, forasmuch as faith could do many things; and hence it follows, And the Lord said, If ye had faith as a grain of mustard seed, &c. Two mighty acts are here brought together in the same sentence; the transplanting of that which was rooted in the earth, and the planting thereof in the sea, (for what is ever planted in the waves?) by which two things He declares the power of faith.