Answered by Imam Yama Niazi
If I am not wrong, Allah(swt) said not to disrespect any other religion. So while talking to the family, if I disrespect any other religion, will I be sinful for that?
Assalam alaykum wa rahmatullah
May Allah bless you and increase you in good.
There is an ayah that you may be alluding to that mentions the following:
˹O believers!˺ Do not insult what they invoke besides Allah or they will insult Allah spitefully out of ignorance… [Quran 6:108]
That refers to the consequences behind those actions. Imam Qurtubi says about this ayah that the reason is that if they know or hear of it, then they would be averse to faith and would even increase in their disbelief [Tafsir Qurtubi]
Furthermore, there is also a hadith that mentions:
Narrated `Abdullah bin `Amr: Allah’s Messenger (peace and blessings be upon him) said. “It is one of the greatest sins that a man should curse his parents.” It was asked (by the people), “O Allah’s Messenger (peace and blessings be upon him)! How does a man curse his parents?” The Prophet (peace and blessings be upon him) said, “‘The man abuses the father of another man and the latter abuses the father of the former and abuses his mother.”
Hence, we need to avoid any word or deed which leads others to sin.
This is based upon a principle that some scholars mention,
“Leaving off a benefit because of harm that may ensue.” (Tafsir ibn Kathir)
As for cursing idols or other false beliefs when no one is present who would be offended, this would be permissible due to no harm being ensued.
I recommend that you refrain from it unless there is an apparent reason for it and spend your time on more important matters.
Allah knows best.
[Imam] Yama Niazi
Checked and Approved by Shaykh Faraz Rabbani