Prophet Musa (as) was once walking along the seashore when a fisherman came by, and prostrated himself before the Sun, uttering words of polytheism. Then he threw his fishing net into the sea, and drew it out filled with fish. Then he threw it in again, and once again, it came out full. Once more he repeated this, and once again, it came out full, until he was satisfied then he departed.
Then, another man came along, performed the ablution and stood in prayer, praising and glorifying Allah. Then, he flung his net in, but drew it back empty. So he repeated this, and again, he met with no success. Once again, he threw his net in, and this time he caught a small fish. So, he praised and thanked Allah and went off.
Seeing this, Musa (as) called out, ‘O Lord! When Your servant came along and denied You, praying to the Sun and uttering blasphemy, his net was filled with fish repeatedly until he was satisfied and left. And when Your believing servant came along, performed the ablution, prayed, glorified, praised, and supplicated to You and then threw his net in, he received nothing but a small fish?’
So, Allah revealed to him, ‘O Musa! Look to your right.’ Musa looked, and it was revealed to him what Allah had set aside in reward for the believing servant. Then, it was said to him, ‘O Musa, now look to your left.’ And he saw what punishment was awaiting the disbelieving servant.
Then Allah spoke, ‘O Musa, in reality, the one whom I gave did not benefit anything, nor did the one whom I deny lose anything.’
‘O Lord!’ responded Musa (as), ‘Indeed, it is the duty of all that know You, to be content with whatever You do for them.’
[A`lam al-Din 267]