Is it obligatory for a scholar to testify to a matter, even if he is not asked to do so?

Question:
He says: If I know of a testimony, and I am not asked to testify, is there a sin on me for that?

Answer:
If the person who has the right does not have witnesses and fears that his right will be lost, and you have testimony while he is unaware of your testimony, then you should make it known to him so that his right is not lost. However, if he knows about your testimony and does not ask for it, you are not required to give it, for the verse states, "They do not refuse to give testimony when they are called." He did not call you, and he knows that you have testimony. But if he does not know that you have testimony and his right is about to be lost, then you must give the testimony. Yes.