The Lord God Almighty is a covenant keeping God and a Rewarder.
Abraham served God and he end up being a blessed man even uptil today. A father of nations.
David served God and the throne was not totally taken away from him and his lineage because God remember His covenant with David. Today David is a well known figure many century after. Don't forget Our Lord Jesus came into this world through the lineage of David.
To sum it all it pays to serve God in truth and in spirit