24 But although the sparrows will build in the cedars of Libanus, “the house of the coot is their leader.” What is the house of the coot? The coot, as we all know, is a water bird, dwelling either among the marshes, or on the sea. It has rarely or never a home on the shore; but in places in the midst of the waters, and thus usually in rocky islets, surrounded by the waves. We therefore understand that the rock is the fit home of the coot, it never dwells more securely than on the rock.
On what sort of rock? One placed in the sea. And if it is beaten by the waves, yet it breaks the waves, is not broken by them: this is the excellency of the rock in the sea. How great waves beat on our Lord Jesus Christ? The Jews dashed against Him; they were broken, He remained whole. And let every one who does imitate Christ, so dwell in this world, that is, in this sea, where he cannot but feel storms and tempests, that he may yield to no wind, to no wave, but remain whole, while he meets them all.
The home of the coot, therefore, is both strong and weak. The coot has not a home on lofty spots; nothing is more firm and nothing more humble than that home. Sparrows build indeed in cedars, on account of actual need: but they hold that rock as their leader, which is beaten by the waves, and yet not broken; for they imitate the sufferings of Christ....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)