Jesus often went off alone so that He could spend time with the Father.  In Mark 6:31, we see Jesus calling His disciples apart for rest.  Many Christians have neglected the needs of their physical bodies and have cut their ministries short through death or severe illness.   Many have failed to take the time to be still and know God (Psalm 46:10). This will also cut your ministry short through non-effectiveness. 

One of Satan's deadliest weapons against those involved in ministry is busy-ness.  We must balance our time ministering to others with our time of being ministered to by our Father.  If the devil can't stop us from "getting on fire" for God, then he'll try to stop us by getting us "burned out."

Remember, the reason Jesus and His disciples were going to this remote place was to get away from the multitude for awhile and rest. This rest was not optional, it was, a necessary.   However, the multitude followed them and their rest ended even before it began.  Surely, Jesus and His disciples were disappointed. But instead of anger or bitterness, Jesus was moved with compassion.

Later on in the evening, Jesus went up into a mountain and prayed until the fourth watch (3 to 6 a.m.). The Lord intends for us to take care of our physical bodies as can be seen by Jesus' actions in taking His disciples aside for rest.  But when this purpose was frustrated by the demands of the ministry, Jesus gave priority to the spirit man and stayed up all night praying and getting the spiritual rest He was needing. We should follow His example and always put the needs of the spirit ahead of the needs of the flesh.