"The experience of the disciples in the Garden of Gethsemane contains a lesson for the Lord's people today. Taking with Him Peter and James and John, Christ went to Gethsemane to pray. He said to them: “My soul is exceeding sorrowful unto death: tarry ye here, and watch. And He went forward a little, and fell on the ground, and prayed that, if it were possible, the hour might pass from Him. And He said, Abba Father, all things are possible unto Thee; take away this cup from Me: nevertheless not what I will, but what Thou wilt. And He cometh, and findeth them sleeping, and saith unto Peter, Simon, sleepest thou? couldest not thou watch one hour? Watch ye and pray, lest ye enter into temptation.” Mark 14:34-38 . 8T 100.2"
"And saith unto them, My soul is exceeding sorrowful unto death: tarry ye here, and watch. And he went forward a little, and fell on the ground, and prayed that, if it were possible, the hour might pass from him. And he said, Abba, Father, all things are possible unto thee; take away this cup from me: nevertheless not what I will, but what thou wilt. And he cometh, and findeth them sleeping, and saith unto Peter, Simon, sleepest thou? couldest not thou watch one hour? Watch ye and pray, lest ye enter into temptation. The spirit truly is ready, but the flesh is weak."
Ellen White directly references Mark 14:34-38 in this passage.