Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 22:43-46

“Or this is proverbially said of one who has sweated intensely, that He sweated blood; the Evangelist then wishing to shew that He was moistened with large drops of sweat, takes drops of blood for an example. But afterwards finding His disciples asleep for sorrow, He upbraids them, at the same time reminding them to pray; for it follows, And when he rose from prayer and was come to his disciples, he found them sleeping.”