Markus 14:38-40

14:38 Stay awake and pray that you will not fall into temptation. The spirit is willing, but the flesh is weak.” 14:39 He went away again and prayed the same thing. 14:40 When he came again he found them sleeping; they could not keep their eyes open. ¹  And they did not know what to tell him.

[14:40]  ¹ tn Grk “because their eyes were weighed down,” an idiom for becoming extremely or excessively sleepy (L&N 23.69).