Assalaamu alaykum. What is the ruling on randomly saying 'Astaghfirullah Rabb-al-Aalameen' (I seek forgiveness from Allaah, the Lord of the worlds), meaning not at the end of specific acts of worship but, rather, when driving, or when someone gives me excessive accolades which I do not deserve, or when seeing something that is a Fitnah (temptation, tribulation), and other than this? This is not to be confused with saying 'Astaghfirullah' (I seek forgiveness from Allaah) by itself, as we have been instructed to do in hadiths. May Allaah reward you.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

We do not know of any religious impediment to seeking forgiveness by saying 'Astaghfirullah Rabb-al-'Aalameen'. In seeking forgiveness and reciting general Thikr (expressions of remembrance of Allah) and supplications, it is not a condition to abide by the specific wordings reported in religious texts; rather, a person is allowed to seek forgiveness using any wording of his choice as long as it does not indicate meanings that are prohibited by the Shariah.

Ibn ‘Uthaymeen was asked about adding the words 'wa Ta‘aalayta' (and Exalted are You) to the supplication reading 'Allahumma Anta As-Salaam wa Minka As-Salaam, Tabarakta wa Ta‘aalayta ya Thal-Jalaali wal-Ikraam' (which is recited after the Tasleem to conclude prayer).

He answered:

"It is better not to add this word in that place (after the prayer) because the Prophet, sallallahu ‘alayhi wa sallam, did not say it in that place. Rather, he, sallallahu ‘alayhi wa sallam, used to say upon concluding the prayer, 'Allahumma Anta As-Salaam wa Minka As-Salaam, Tabaarakta ya Thal-Jalaali wal-Ikraam.' There is no problem in adding the extra words (wa Ta‘aalayt) or the like in other places because there is no religious impediment to praising Allah as such (saying 'Blessed and Exalted are You'), and this addition does not indicate a wrong meaning. As for the reported Thikr from the Prophet that is to be recited in a certain time or place, it is better to recite it as it is without addition or omission. However, there is no harm in adding to it in other times or places where there is no reported forbiddance to recite Thikr." [Fatwaa ‘alaa Ad-Darb]

Allah knows best.