And He took with Him Peter and the two sons of Zebedee, and He began to be sorrowful and deeply distressed.  Then He said to them, "My soul is exceedingly sorrowful, even to death. Stay here and watch with Me." 

He went a little farther and fell on His face, and prayed, saying, "O My Father, if it is possible, let this cup pass from Me; nevertheless, not as I will, but as You will." 

Then He came to the disciples and found them asleep, and said to Peter, "What? Could you not watch with Me one hour?  "Watch and pray, lest you enter into temptation. The spirit indeed is willing, but the flesh is weak." 

Again, a second time, He went away and prayed, saying, "O My Father, if this cup cannot pass away from Me unless I drink it, Your will be done." 

And He came and found them asleep again, for their eyes were heavy.  So He left them, went away again, and prayed the third time, saying the same words.  

Matthew 26:36-44  (NKJV)