Ayat to Pass by Unseen

بِسۡمِ ٱللهِ ٱلرَّحۡمَـٰنِ ٱلرَّحِيمِ 

This is the ayat recited for those who seek to pass by unseen: 

سُوۡرَةُیسٓ

إِنَّاجَعَلۡنَا فِىٓ أَعۡنَـٰقِهِمۡ أَغۡلَـٰلاً۬ فَهِىَ إِلَى ٱلۡأَذۡقَانِ فَهُممُّقۡمَحُونَ (٨) 

Innaa ja’alnaa fii a’anaaqihim aghlaalan fahiya ilaa al-adzqaan fahum muqmahuun. 

We have Put yokes round their necks right up to their chins, so that their heads are forced up (and they cannot see). (Surah YaSin:8) 

This is the ayat the Prophet (s.a.w.) read, when he passed by the Quraysh who waited to assassinate him.  He picked up sand or dust, and blew it in their direction.