Reference: Siyar A’laam an-Nubalaa – Volume 4, Page 207
Abul-’Aaliyah said:
And al-i’tisaam is to have complete trust and confidence in Allaah; and [know thereafter] whoever supplicates to Him, He will respond. And what affirms that in the Book of Allaah [is]:
{And when My servants ask you, [O Muhammad], concerning Me – indeed I am near. I respond to the invocation of the supplicant when he calls upon Me.}, soorah al-Baqarah, aayah 186