Is the lack of answer to a supplication considered proof of the supplicant's sin or Allah's displeasure with him, especially when adhering to acts of worship and seeking out times of response, and is this an indication that the supplicant is among those who are impatient?

Du'a (supplication) is a great act of worship for which Allah will not disappoint its supplicant. However, the answer to it is withheld if the supplicant is hasty and says, "I supplicated, but I was not answered," or if he supplicates for a sin or for the severing of kinship ties. Allah answers supplications in one of three ways: He either grants him what he asked for, or He averts from him an equivalent evil, or He stores it for him in the Hereafter. One should persist in supplication and not despair.