Fear vs. love

"For I dreaded destruction from God, and for fear of his splendour I could not do such things." Job 31:23
In Job 31, Job lists a number of sins that he had not committed. He did not look lustfully at women, he did not take advantage of the poor, he treated everyone fairly. But here in v23, he gives the reason for living this way: for fear of God's judgement coming upon him.
Christians can obey God for one of two reasons. First, they may be like Job, obeying God because to disobey Him would bring judgement and discipline. They obey God out of fear. Now, we are to have a healthy fear of God, giving Him the respect He deserves but not being afraid of Him.
The second motivation a Christian may have from which they serve and obey God, is out of love and gratitude for Him. Now, the tables are turned: we don't obey God because of the pain that He might cause to us, but we obey Him because we don't want to cause Him pain. Of the two, love is the greater motivator.
"There is no fear in love. But perfect love drives out fear, because fear has to do with punishment. The one who fears is not made perfect in love" (1 John 4:18).