الَّهُمَّ إِنِّي أَعُوذُ بِكَ أَنْ أَضِلَّ أَوْ أُضَلَّ، أَوْ أَزِلَّ أَوْ أُزَلَّ أَوْ أَظْلِمَ، أَوْ أُظْلَمَ، أَوْ أَجْهَلَ، أَوْ يُجْهَلَ عَلَيَّ
Allaahumma 'innee 'a'oodhu bika 'an 'adhilla 'aw 'udhalla, 'aw 'azilla ‘aw ‘uzalla ‘aw ‘adhlima ‘aw ‘udhlama, ‘aw ‘ajhala ‘aw yujhala ‘alayya
O Allah, I seek refuge in You lest I misguide others, or I am misguided by others, lest I cause others to err or I am caused to err, lest I abuse others or be abused, and lest I behave foolishly or meet with the foolishness of others
[Abu Dawud, Ibn Majah, An-Nasa'i, At-Tirmizi, Al-Albani, Sahih At-Tirmizi 3/152, Sahih Ibn Majah 2/336]
Asking for protection from Allah is something that Muslims must do before starting their activities. One of them is by reciting this beautiful dua before leaving the house. This dua was quoted from Umm Salamah RA, one of the wives of the Prophet Muhammad SAW, that whenever Prophet SAW left the house this dua was always recited while looking towards heaven. This implies that the dua was recited to ask for Allah's protection during his journey or whenever he was out of his house's comfort and safety.
What does the dua's protection refer to? It does not only mean protecting the person who recited them, but also people who would be around, interact with, or others that would cross paths with them. It also had a meaning that the protection was beyond only being physically safe, but also from words, gestures, and other sins that we could possibly commit unintentionally and harm others—be it small or big in effect. Hence why it mentions being misguided or misguiding others, abusing others or being abused, and so on.
Remember to also recite this dua beforehand in order to complete the whole complete practice of the dua. By reciting this dua beforehand, you are trusting everything to Allah's might and help by the time you stepped out of your house.
بِسْمِ اللَّهِ تَوَكَّلْـتُ عَلَى اللَّهِ، وَلاَ حَوْلَ وَلاَ قُـوَّةَ إِلاَّ بِاللَّهِ
Bismillaah tawakkaltu 'alallaah wa laa hawla wa laa quwwata 'illaa billaah
In the Name of Allah, I place my trust in Allah and there is neither might nor power except with Allah
[Abu Dawud 4:325, At-Tirmidhi 5:490]
May reciting this dua and giving our trust fully to Allah, kept us safe in every single way through the blessings of Allah. Amin.
Read more about the Manners and Dua When Leaving Home And Entering Home.