The ignorant among us complain to people about Allah, and this is the highest degree of ignorance. If one knew his Lord, he would never complain about Him; and if knew the (reality of) people, he would not complain to them.
One of the predecessors saw a man complaining to another man about his poverty and dire necessity, so he said to him, “O you! By Allah, you have done nothing but complain about He who has mercy for you, to someone who has no mercy for you.”
A poet said: When you complain to a son of Adam, verily you complain about the Most Merciful, to the one who does not have any pity.
On the contrary, a person who is profoundly knowledgeable about Allah complains to Allah alone, and never to the people. He complains about the causes because he knows the verses:
“And whatever of misfortune befalls you it is because of what your hands have earned. And He pardons much.” (Qur’an, 42:30)
“Whatever of good reaches you, is from Allah but whatever of evil befalls you, is from yourself.” (Qur’an, 4:79)
“(What is the matter with you?) When a single disaster smites you, although you smote (your enemies) with one twice as great, you say: ‘From where does this come to us?’ Say (to them), ‘It is from yourselves (because of your evil deeds).’ And Allah has power over all things.” (Qur’an, 3:165)
The lowest of people complain about Allah to His creatures, while the highest of people complain about their own-selves to Allah.