Backbiting

Salamu alaikum

-If asking forgiveness may sour relations significantly should we ask?
-Is it obligatory to ask forgiveness from non muslims?

wa alaikum salam,

1. here you have to consider two things, there are in the Islamic law ibadat and muamalat, as far as your question is concerned,because its about relation with your fellow human beings, it is muamalat. In questions of Akhlaq and Adab, many things are not mandatory or forbidden, but rather mandub and makruh. As for sins, there are sins that relate to your Lord -most high- and sins that relate to your fellow human beings. So if it is a matter in which you have harmed someone else's religious given right, you must go there as well as you ask Allah for forgiveness and ask the person to forgive you. but if it is not a sinful act but rather is only interpersonal and has no religious relationship, it is up to you to decide whether to apologize or not. Some scholars would first ask what it is about and whether it is important to you and to what extent it would harm you. For some scholars, it is said that in order not to disappoint your spouse and avoid damage to your marriage, you can keep silent (but not lie) as long as it is not serious. (Example: The husband does not mention that he cannot stand the in-laws).

As for backbiting of a muslim it is a sin but not everything what people deem as backbiting is backbiting so you have to first look what was said. Then you can determine if you did backbiting and sinned. Then you do tawbah and after that you ask the person for forgiveness.

2. Rules on relationship of muslims and non muslims are very detailed and depend heavily on your and their status, like as a example as a muslim you cannot be friends with a non muslim who is an open enemy to islam. so your second question depends heavily on many details.

wa salam