Matthew 26:43

‘And he came again and found them sleeping, for their eyes were heavy.'

And once again He returns to the three and finds them asleep, for their eyes just would not stay open. Their weakness of flesh was constantly overcoming their spirit. (Old age especially brings out this weakness of the flesh when often for some it is impossible to keep awake, which is the origin of the idea of ‘forty winks'. But these were comparatively young men. It should not have been so with them. They have become prematurely old).