Protected Pearls

The Ignorant complains about Allah to people, and this is considered to be the utmost ignorance from both the complainer and the one who is being complained to, because if this complainer knows Allah well, then he won’t complain about Allah.  Also if he knows people well, then he won’t ever complain to them.  Some of the Salaf (Worthy Ancestors) saw a man complaining to another his dear need and poverty, he told him: O man, I swear that you benefit nothing except that you complain about the Merciful, who is kind to you, to the merciless, that won’t be kind to you as Him. And in this situation it was said:

If you complain to Adam’s son, you’re only complaining about the Merciful to the merciless

The knowledgeable, who knows Allah, will only complain to Allah. While, the most knowledgeable is who complains to Allah about himself and not about people so, he complains from the reasons and causes which imposed upon him the power of people, because he knows what Allah says:  “And whatever strikes you of disaster - it is for what your hands have earned” [Quran 42:30]

and “what comes to you of evil, [O man], is from yourself.”[Quran 4:79]

and “Why [is it that] when a [single] disaster struck you [on the day of Uhud], although you had struck [the enemy in the battle of Badr] with one twice as great, you said, "From where is this?" Say, "It is from yourselves." [Quran 3:165]

that’s why he knows that these disasters  stroked him only because of himself and what he has committed so he complains himself and what he did to The Merciful.

There are three level of complaining:

The lowest level is that you complain to people about Allah, the highest level is that you complain about yourself to Allah. While the middle level is that you complain about people (Allah’s creatures) to Allah, Their Creator.

Translated from "the book of repentants" for Ibn Qudamah