As-Sayyid ar-Radi says: This is confirmed by the Book of Allah. About praying, Allah says: "Call you to Me, I will answer you" (Qur'an, 4:60). About forgiveness Allah says: "And whoever does evil, or wrongs his own self and thereafter seeks pardon of Allah, shall find Allah Oft-forgiving, Merciful" (Qur'an, 4:110). About gratefulness He says: "If you be grateful I will increase (my favours) to you" (Qur'an, 14:7). About repentance He says: "Verily, repentance (acceptable) with Allah is only for those who do evil ignorantly and then turn (to Allah) soon (after); these (are those) Allah will turn (merciful) to them; and Allah is All-knowing, All-wise" (Qur'an, 4: 17).