Allah Most High’s words,

“Call upon Me; I will answer you,”

have been interpreted in both senses. One interpretation is: “Worship Me and obey My command; I will answer you.” As Allah Most High says:

“He answers those who believe and do righteous deeds.”

That is, He responds to them. This usage is well established in Arabic: both istajābahu and istajāba lahu mean “he answered him.” As the poet said:

A caller cried, “O you who answer the call to generosity!”
Yet no one answered him then.

The other interpretation is: “Ask of Me; I will give to you.”

In the two Sahīh collections, the Prophet (may Allah bless him and grant him peace) is reported to have said:

“Our Lord descends every night to the lowest heaven when the last third of the night remains, and says: ‘Who calls upon Me, that I may answer him? Who asks of Me, that I may give to him? Who seeks My forgiveness, that I may forgive him?’”

He first mentions calling upon Him, then asking and seeking forgiveness. The one who seeks forgiveness is asking, just as the one who asks is calling upon Him. However, mentioning the one who asks for harm to be averted after the one who asks for good, and mentioning both after the one who calls upon Him—a description encompassing them both and others besides—is an instance of mentioning the specific after the general.

Allah Most High says:

“When My servants ask you about Me, I am indeed near. I answer the invocation of the one who calls upon Me when he calls upon Me.”

Every petitioner has hope and fear, and thus worships the One he petitions; and everyone who worships Him