What is our motivation to serve the LORD? Most “churches” induce people to work for God with one of two methods (generally with a mixture of the two).
 Threats of Punishment.
Many preachers instill within their hearers a need to be faithful and serve God otherwise the LORD will lay heavy stripes upon them. By this tactic people are moved to activity by a fear of what God will do to them if they don’t obey Him. They therefore attend, give, and try to serve God out of slavish fear. “If you don’t tithe, God will get His money at the doctor’s office, or at the auto repair shop. If you don’t attend, God will make you sick so you will not be able to attend.” The motivation, therefore, is not to gratefully and lovingly serve God for His glory, but serve Him in order to keep the Lord off your back and to keep you out of the proverbial dog house!
 Promise of Rewards.
This motivating principle says that the more you do for the Lord, the more He will give you when you get to heaven. Do a lot and get a lot; do little and get little. This is a mercenary motivation, laboring for wages.
Years ago I sat under the ministry of preachers who said to us that it will be very sad for some Christians when they get to heaven. They will arrive there by the skin of their teeth and receive no rewards from God because they did not serve Him. One professor in the Bible College I attended used to teach that there will be some believers in heaven who will live in a mansion on Main Street, having earned a higher place in the kingdom of God by their faithfulness and good works. Others, however, will live in a shack in the slum section of heaven and be ashamed that they didn’t obey the LORD and earn some rewards. What nonsense!
In the Word of God, neither threats or rewards are used by the inspired writers to move the children of God to serve Him in this world. The motivating principle is always to serve the LORD with thanksgiving and love because of what He has done for us through and by Christ Jesus. Paul said, “The love of Christ constraineth us” (2nd Corinthians 5:14). When the apostle would encourage the Roman believers to a life of commitment to the LORD, he did not use threats of punishment nor did he use the promise of rewards. He said, “I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service” (Romans 12:1). God has showed us mercy for Christ’s sake. All of our sins were washed away in the river of Christ’s blood. He satisfied the demands of the law and by His atonement He fully and finally put away our sins. It is, therefore, the most reasonable thing in this world to serve the LORD in light of all He has done for me! We are not slaves, afraid of what the Master will do to us if we don’t serve Him, we are sons and rejoice to labor in the cause of God. And we do not serve as hirelings, for reward. We want no more than Christ! “The LORD is my Portion said my soul” (Lamentation 3:24). I shall, therefore, seek to serve Him in this world moved by the most effectual of all motivating principles, the power of love – Christ’s love to me, and my God-given love for Him. And if I am privileged to serve Him and do good things in this world, I desire no credit, for my service to the LORD is only because of His enabling grace. The LORD, therefore, must (and shall) receive all the glory. “For we are His workmanship created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.” (Ephesians 2:10)