The way (to blame) is only against those who ask permission of you though they are rich; they have chosen to be with those who remained behind, and Allah has set a seal upon their hearts so they do not know.

But if you do not find any one therein, then do not enter them until permission is given to you; and if it is said to you: Go back, then go back; this is purer for you; and Allah is Cognizant of what you do.

And We did not send any apostle but that he should be obeyed by Allah's permission; and had they, when they were unjust to themselves, come to you and asked forgiveness of Allah and the Apostle had (also) asked forgiveness for them, they would have found Allah Oft-returning (to mercy), Merciful.

And no blame is on you if he would not purify himself / And as to him who comes to you striving hard, / And he fears, / From him will you divert yourself.

And strive hard in (the way of) Allah, (such) a striving a is due to Him; He has chosen you and has not laid upon you an hardship in religion; the faith of your father Ibrahim; He named you Muslims before and in this, that the Apostle may be a bearer

Sometimes it's easier to ask forgiveness than to ask permission.