Summary: There is a growing belief that the better a Christian behaves or does things for God, the greater their rank and job responsibilities will be in the heavenly kingdom - and they will also be rewarded with a deeper relationship with God.
There are primarily two schools of thought that have emerged over the years about what the reward of Heaven will be. Some believe that there will be different gifts and varying degrees of happiness in Heaven based upon a merit type of system done on earth and how well a person works at their Christian life in holiness and obedience to God's commands.
Others believe that the only valid reward a Christian receives at the moment they release all claims to their life and receive Jesus Christ as their personal Lord and Savior is eternal salvation because nothing else matters.
Although there are no Scriptures that explicitly declare these beliefs, there is the insistence that the Scriptures' imply' them. The Bible tells us that those Christians who build the foundation of their life - or their ministry - upon their good works just as the church at Corinth was doing, "will be revealed with fire and the fire will test the quality of each man's work." (1 Cor 3:10-15) The works that are not done to God's glory are "rubbish" and will be destroyed;
"But what things were gain to me, these I have counted loss for Christ. Yet indeed I also count all things loss for the excellence of the knowledge of Christ Jesus my Lord, for whom I have suffered the loss of all things, and count them as rubbish, that I may gain Christ" (Phil 3:7-8 NKJV)
Christians must be "careful" how they build upon the only foundation of the Church, which is Jesus Himself. Those who are active in ministry must recognize that it is a holy endeavor and not to be taken lightly. Just as Christians are to have an attitude of fear and trembling when considering that it is the holy God alone who is working out their salvation within them (Phil 2:12-13), so it is with ministry and service within the Church.
When a Christian comes to the place of knowing beyond a shadow of a doubt that their salvation is based upon what Jesus has done and not what they do - or don't do - for Him, they will never worry about being faithful and building their life, or ministry, upon their self-made foundation.
Some would contend that the touted merit system of heavenly hierarchies is antithetical to Christianity. They would assert that the underlying principle of Jesus' words that the "last shall be first and the first last" turns this belief upside down as the top 'performers' actually become the bottom 'performers' and those at the bottom go to the top (Matt. 20:16, 19:30, 23:12; Luke 14:11).
The Great Reward
Every Christian receives a reward for the work of Jesus because He alone is the One who did the work and sent the Holy Spirit to ensure they would bring forth fruit by His faith (Matt. 5:12; Eph 2:8-10). There are two words translated "reward" in the New Testament. They are 'apodidomi,' which means to give away, give over, give back, (Matt 6:4, 16:27; Rom 2:6; 1 Thess 5:15; 2 Tim 4:14; Rev 22:12), and 'misthos,' which means to hire and pay for services. This is the most widely used word for "reward" (Matt 5:12,46; 6:1; 10:41; Mark 9:41; 1 Cor 3:8,14).
The Christian has already been judged for their works and has been justified by the shed blood of Jesus. Jesus made the Christian perfect in every good work, and they will have a full 'reward' - which is their inheritance of everlasting life that He alone secured for them.
"For I say, through the grace given unto me, to every man that is among you, not to think of himself more highly than he ought to think; but to think soberly, according as God hath dealt to every man the measure of faith." (Rom 12:3 KJV)
No matter how hard, or good, or long a Christian works at being a fully devoted follower of Jesus, they all receive the exact same "reward" for what they have done. As shown in the Parable of the Vineyard Workers, the payment or reward for works performed on the Earth is not based upon the value of their service, but upon the purpose of God's work of grace (Matt 20:1-16). God has blessed every Christian with the full reward of "all spiritual blessings," and their name has been written in the Lamb's Book of Life! (Rev 3:5)
It is only by grace that the Christian is fully accepted in Jesus (Col 3:24; 2 Tim 1:9). The "works" of the Christian are finished, and they now "rest" in Jesus (Matt 11:28). They are not working for anything because they have been given everything in Him. The Christian is "complete," and they receive a full and complete reward because their works are of the Holy Spirit, and they are judged as being in Christ (Col 2:9-10).