Abu Hurairah relates that Prophet Muhammad ﷺ said, “Allah, the Exalted says: I declare war against one who bears enmity towards a friend of Mine. When a servant of Mine comes closer to Me, with a thing which I love, out of things which I have prescribed; and when he seeks My favour through optional prayers (nawafil), I start loving him and when I love him, I become his ear with which he hears, and his eyes with which he sees, and his hand with which he grasps, and his foot with which he walks; and when he requests Me for anything, I grant him and when he seeks protection, I give him protection.”
(Sahih Bukhari)
The hadīth highlights the importance of optional prayers (nawafil), which is one of the best means of man’s coming closer to Allah. Here the Blessed Prophet says that Allah loves optional prayers. It is so because man performs these prayers besides the obligatory prayers, just to seek the pleasure of Allah. When he does so, Allah the Exalted begins to love him.
That Allah becomes his ear with which he hears means that he likes to hear only what Allah permits and shuns all that He forbids. Similarly, he sees only what Allah permits and keeps from what is forbidden; he uses his hands and feet only in accordance with the teachings of Allah and His Messenger. When such a blessed person requests Allah for anything, He grants him his prayer; and when he seeks protection, Allah gives him protection.