Hebrews 11:6 And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him.
Hebrews 11 describes people whose faith resulted in action and good works. Abel offered good sacrifices, Noah built a boat, Abraham left his home. They sought God earnestly and, according to verse 6, were obligated to believe God would reward them. But this should not be confused with God being obligated to reward us. Or put more simply, that God needed to repay us.
An analogy might be a child living with his parents. Perhaps the child had been especially well behaved and obedient. As a result the parents had promised he would receive a special Christmas present. This present is not payment for his good behaviour. If a reckoning were done it would be found that the child was incredibly indebted to the parents. They are the ones who pay for his clothing, food, education, accommodation, entertainment and toys. The obedience demonstrated by the child does not place his parents in his debt. In fact the child is not capable of repaying his parents for all they expend on him. His obedience is simply a sign of his appreciation and love for all they do.
If that is true of what he receives on a daily basis, it is even more true of presents received on special occasions. A present is not payment from a parent to the child for obedience rendered. It is a sign of their love for their child and an acknowledgment of his love for them. It is this sort of reward that we must expect from our loving heavenly Father.
Our obedience doesn’t earn us favour from God. However our disobedience does earn us his anger. In the same way that a lazy and rebellious child may eventually be forced to leave the home, a disobedient Christian may also be rejected by God. Their rejection was due to their bad works does not imply that their acceptance in the family is because of their good works. He earns his rejection. He does not earn his acceptance.