Is it permissible to say "if only" regarding past matters if they were good?

Question:
May Allah reward you, Your Eminence, father. This questioner says: Some people have said that it is permissible to say "if only" regarding past good things, such as saying, "If I had attended the lecture, I would have benefited." Is this correct?

Answer:
No, that is not correct. You do not say "if only" regarding the past, but there is no harm in saying it regarding the future. There is no harm in saying, "If only I had built myself a house," "If only I had bought myself a car," or "If only it had been better for me." There is no objection to that. Yes.