What to say upon leaving the house
Anas (radi Allahu anhu) reported the Messenger of Allah (sal Allahu alaihi wa sallam) said, “Whoever says (upon leaving his house): ‘Bismillah, tawakkaltu ‘alallah, wa la hawla wa la quwwata illa billah [I begin with the Name of Allah; I trust in Allah; there is no altering of conditions but by the Power of Allah]’ it will be said to him: ‘You are guided, defended and protected.’ The devil will go far away from him.”
[Abu Dawud, At-Tirmidhi and An-Nasa'i]
Abu Dawud reported it with this addition: “One devil will say to another: ‘How can you deal with a man who has been guided, defended and protected?”
The prayer quoted in this Hadith shows the importance of confidence and trust in Allah and request for security against the mischief of Satan.
And Allah Knows Best!