Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 21:37-38

“Now the Evangelists are silent as to the greater part of Christ’s teaching; for whereas He preached for the space nearly of three years, all the teaching which they have written down would scarcely, one might say, suffice for the discourse of a single day. For out of a great many things extracting a few, they have given only a taste as it were of the sweetness of His teaching. But our Lord here instructs us, that we ought to address God at night and in silence, but in day time to be doing good to men; and to gather indeed at night, but in the day distribute what we have gathered. As it is added, And at night he went out and abode in the mount that is called Olivet. Not that He had need of prayer, but He did this for our example.”