´Mus'ab bin Sa'd narrated that his father said:` "I swore by Al-Lat and Al-'Uzza and my companions said to me: 'What a bad thing you have said! You have said something horrible.' So I went to the Messenger of Allah and told him about that. He said: 'Say: La ilaha illallah wahdahu la sharika lah, lahul-mulk wa lahul-hamd wa huwa 'ala kulli shay'in qadir (There is none worthy of worship except Allah with no partner or associate; His is the Dominion, to Him be all praise, and He is able to do all things). Spit to your left three times, seek refuge with Allah from the Shaitan, and do not say that again.'"
Hadith Referenceسنن نسائي / كتاب الأيمان والنذور / 3808
Hadith Gradingالألبانی:ضعيف | زبیر علی زئی:إسناده صحيح
It was, therefore, a satanic whispering for which the Messenger of Allah (sallallahu alayhi wa sallam) prescribed a remedy: remember Allah, spit to your left with aversion towards Satan, and verbally recite: "A'udhu billahi min ash-shaytan ir-rajim."
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 3808
´It was narrated from Mus'ab bin Sa'd that his father said:` "We were talking about something, and I had only recently left Jahiliyyah behind, so I swore by Al-Lat and Al-'Uzza. The Companions of the Messenger of Allah said to me: 'What a bad thing you have said! Go to the Messenger of Allah and tell him, for we think that you have committed Kufr.' So I went to him and told him, and he said to me: 'Say: La ilaha illallah wahdahu la sharika lah (There is none worthy of worship except Allah alone, without partner) three times, and seek refuge with Allah from the Shaitan three times, and spit dryly to your left three times, and do not say that again.'"
Hafiz Muhammad Ameen
(1) Sa'd radi Allahu anhu was among the very earliest Muslims. He is included among the Sabiqun al-Awwalun (the first and foremost). Only a few elders had accepted Islam before him. According to his own account, he was the third person to become Muslim. He is included among the 'Asharah Mubasharah (the ten given glad tidings of Paradise). Radi Allahu anhu wa ardahu.
(2) Al-'Uzza was also an idol which was commonly worshipped. In the Age of Ignorance (Jahiliyyah), it was customary to swear oaths by idols. He too, unintentionally and out of habit, swore such an oath. (For details, see the previous hadith.)
(3) If a person commits a sin, it is obligatory (wajib) for him to seek forgiveness (istighfar) for it, and he should not commit that sin again, because this is among the conditions of repentance (tawbah).
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 3807