John Gill Commentary Mark 14:37

"And he cometh, and findeth them sleeping, and saith unto Peter, Simon, sleepest thou? couldest thou not watch one hour?" — Mark 14:37 (ASV)

And he comes and finds them sleeping
His three disciples, Peter, James, and John:

and says to Peter ;
particularly, he having so lately asserted, with so much confidence, his love to Christ, and close attachment to him:

Simon, are you sleeping ?
Christ calls him by the name he first went by, and not by that which he had given him, Cephas, or Peter; he not now having that firmness and constancy, though he boasted of it, which answers to that name:

could you not watch one hour ?
The Arabic and Persic versions add, with me; and so does the Complutensian edition; (See Gill on Matthew 26:40).