The time He chose was admirable, it was the hour of silence, when the crowd would not disturb Him; the time of inaction, when all but Himself had ceased to labour; and the season when slumber made men forget their woes, and cease their applications to Him for relief. While others found rest in sleep, He refreshed Himself with prayer. The place was also well selected. He was alone where none would intrude, where none could observe: thus was He free from Pharisaic ostentation and vulgar interruption.
Those dark and silent hills were a fit oratory for the Son of God. Heaven and earth in midnight stillness heard the groans and sighs of the mysterious Being in whom both worlds were blended. The continuance of His pleadings is remarkable; the long watches were not too long; the cold wind did not chill His devotions; the grim darkness did not darken His faith, or loneliness check His importunity. We cannot watch with Him one hour, but He watched for us whole nights.
The occasion for this prayer is notable; it was after His enemies had been enraged--prayer was His refuge and solace; it was before He sent forth the twelve apostles--prayer was the gate of His enterprise, the herald of His new work. Should we not learn from Jesus to resort to special prayer when we are under peculiar trial, or contemplate fresh endeavours for the Master's glory? Lord Jesus, teach us to pray.
And it came to pass in those days, that He went out into a mountain to pray, and continued all night in prayer to God."
(Taken from Spurgeon's Daily Devotionals)