Translation of the verse 23 from Surah Luqman : Number of verses 34 - - page 413 - Part 21.
And whoever disbelieved, let not his disbelief grieve you (O Muhammad SAW),. to Us is their return, and We shall inform them what they have done. Verily, Allah is the All-Knower of what is in the breasts (of men).
And whoever has disbelieved - let not his disbelief grieve you. To Us is their return, and We will inform them of what they did. Indeed, Allah is Knowing of that within the breasts.
(31:23) So let the unbelief of the unbeliever not grieve you. *43 To Us is their return and then We shall inform them of all that they did. Surely Allah knows well even the secrets that are hidden in the breasts (of people).
*43) This means to say, "O Prophet, the one who refuses to listen to you, thinks that by rejecting Islam and insisting on unbelief he has harmed you, but in fact he has not harmed you but harmed only himself. If he does not listen to you, you need not bother yourself about him at all. "