The Quran

وَإِن أَحَدٌ مِنَ المُشرِكينَ استَجارَكَ فَأَجِرهُ حَتّىٰ يَسمَعَ كَلامَ اللَّهِ ثُمَّ أَبلِغهُ مَأمَنَهُ ۚ ذٰلِكَ بِأَنَّهُم قَومٌ لا يَعلَمونَ

Muhammad Asad

And if any of those who ascribe divinity to aught beside God seeks thy protection,¹ grant him protection, so that he might [be able to] hear the word of God [from thee]; and thereupon convey him to a place where he can feel secure:² this, because they [may be] people who [sin only because they] do not know [the truth].

Lit., "seeks to become thy neighbour": a metaphorical expression denoting a demand for protection, based on the ancient Arabian custom (strongly affirmed by Islam) of honouring and protecting a neighbour to the best of one's ability.
Lit., "his place of security" (ma'manahu)- i.e., "let him rejoin his homeland" (Razi), which implies that he is free to accept or not to accept the message of the Qur'an: a further re-affirmation of the Qur'anic injunction that "there shall be no coercion in matters of faith" (2:256).