Answer: The first thing that is important to note is what must be disclosed before marriage. What must be disclosed before marriage is something that has an active bearing upon the rights of the husband and wife during the marriage.
In other words, something that would have a significant effect upon the rights of the husband and wife during the marriage. That could be a health concern or something else. As for something that is in the past, has been finished and concluded, and doesn't have an active effect upon the marriage, a sensible decision needs to be made about the consequences of disclosing it or not.
There are many different situations, and the one mentioned in the question is quite specific regarding self-harm that happened when the sister was younger. However, I wanted to keep the question general to benefit others who might be in slightly different situations.
As we said, if it is something active and has a significant effect upon the rights of the husband and wife and continues to do so, then it needs to be disclosed.
Of course, a person can decide whether to disclose it in the first, second, or third meeting, according to what will bring about the best possible result, In shā’ Allah. However, it is important that before any significant steps are taken to confirm the marriage and before any Nikāḥ takes place, anything that is an active concern or a significant problem must be disclosed.
As for things that are in the past but no longer an active concern, a sensible decision needs to be made.
There are consequences to disclosing and consequences to not disclosing. If you were to not disclose, as the question mentions, a person may see the result of that and feel very hurt that you didn't share it with them or that they didn't know about it. This could cause some problems in the marriage.
That may be the case for some people. It may not be the case for others. At the same time, disclosing it could also have consequences.
For some people, it might be a case of disclosing something that Allah has kept hidden. We know the prohibition on exposing what Allah has hidden for us in Islam. For others, the consequences of disclosing may be more severe than not disclosing.
So a sensible decision needs to be made. In this particular case, I would suggest that if the scars are obvious and the person is bound to notice them—and Allah knows best—it may not need to be mentioned right at the very beginning. However, at some point prior to the husband and wife being alone together, the issue should be brought up in a very roundabout and indirect way, with the minimum required to explain the situation, without further discussion.
For example, it may not be necessary to say, "Oh, I used to self-harm." It could simply be a case of saying, "I went through a difficult time around the age of 19. It was a time when I was very depressed and went through a tough period. Alḥamdulillāh, I’m completely out of that now. But I wanted to be honest about that time—it was very difficult for me."
Then, if the person were to notice the scars, you could say, "This is what I was talking about and had mentioned. Alḥamdulillāh, it’s not been a problem for me and isn’t a problem anymore by the grace of Allah."
Again, I’m not sure if I can definitively answer whether you should disclose or not. However, I would encourage you to think of the consequences of disclosing versus not disclosing and which has the greater or more severe consequences.
If you do need to disclose, disclose the minimum necessary to remove any harm. Don’t disclose any more than that.
It doesn’t have to be, "I cut myself on seven different occasions using this and that, and I was found like that, and I went to the hospital." It doesn’t need to be a long discussion. It can simply be telling someone, "I had a bad time during that period, and it was very difficult for me."
This may provide enough background so that if they were to see the scars, they wouldn’t feel they had been lied to or betrayed in some way.
Ultimately, it’s up to the person to judge those consequences. And Allah knows best.
— Answered by Ustadh Muhammad Tim Humble
