The rewards in heaven are those things received by those who have received life.
I bought a Ford car and as a result I received according to what the Ford car has to offer. That is not a very good analogy but if one receives life (salvation) they receive according to what the life has to offer.
If one receives life they receive
1.righteousness
2.Peace
3.Eternal existence
4.love
5. joy
and on and on goes the list.
1 Corinthians 2:9 *But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him.
10 *But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God.
11 *For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God.
12 *Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God.
13 *Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual.
14 *But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.
15 *But he that is spiritual judgeth all things, yet he himself is judged of no man.
16 *For who hath known the mind of the Lord, that he may instruct him? But we have the mind of Christ.