After observing the wicked, Asaph felt his commitment to follow God faithfully was a mistake. Instead of prospering, he experienced more problems. God seemed to be punishing the pure in heart and prospering the proud. [source][source][source]
"He had not been guilty of bloodshed or oppressive activities; so he could say that his hands were washed "in innocence" (cf. Psalm 26:6; Matthew 27:24)." [1][source]
". . . we don"t serve God because of what we get out of it but because He is worthy of our worship and service regardless of what He allows to come to our lives." [2][source]