(My Rasul!) Do not pay attention to them, and say, “Salam”! They will know (the reality of the matter) soon!
Al-muntakhab fi tafsir al-Qur'an al-Karim
Leave thorn alone O Muhammad and decline to recognize them but address them with the customary formula of salutation " peace " so that if they should thunder against you, they would peace at your bidding and you be out of harm's way, then they shall come to know the fatal consequence of their obsession with follies