Answered by Shaykh Yusuf Badat
One of my close non-Muslim friends is getting a nikāḥ done with a Shi’ā girl. He wants me to be his witness. Is this permissible?
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allāh, Most Gracious, Most Merciful.
Jazāk Allāh Khayr/ Thank you for contacting Mathabah Institute.
Being a witness for the paperwork of a non-muslim couple’s marriage, to legally register their marriage in a non-muslim country is mubāḥ (allowed).
Where the matter becomes questionable and impermissible is being a witness for an islamicaly prohibited event such as a muslim woman marrying a non-muslim man. The Almighty instructs that we assist one another in good actions, not prohibited actions.
“Cooperate in righteousness and piety, but do not cooperate in sin and transgression. Be mindful of Allāh.” – (Qur’ān 5:2)
Only Allāh knows best
وَتَعَاوَنُوا عَلَى الْبِرِّ وَالتَّقْوَىٰ وَلَا تَعَاوَنُوا عَلَى الْإِثْمِ وَالْعُدْوَانِ وَاتَّقُوا اللَّهَ – المائدة ٢