Jesus returned and found the disciples sleeping - Mark 14:37
He knew their weaknesses
Jesus told his disciples eariler that evening that they would all abadon him
As Jesus prayed in the garden that night, Peter fell fast asleep leaving him defenseless against the coming temptation
The big fisherman failed Jesus miserably because he relied on his own strength and courage
When you remain prayerfully on alert for those temptations, God can give you the strength and wisdom you need