What is the ruling on one who enters with the imam thinking he is praying tarawih, only to find out he is praying 'Isha'?

Question : This questioner says: I love you for the sake of Allah, and my question is that I prayed with the imam intending tarawih. When I realized he was praying the obligatory prayer, and when he stood for the third rak'ah, I knew he was praying the obligatory prayer, so I then intended the obligatory prayer. Is my prayer valid? Knowing that I repeated the prayer after finishing the prayer with the imam. May Allah reward you with good.

Answer : I say: May Allah love the one who loves me for His sake, and may He make us all among the close friends of Allah the Exalted and His awliya. I am in doubt about the validity of the question in this form, because he says he entered with the imam intending tarawih, and it became clear to him that the imam was praying the obligatory prayer. The natural order is to enter with the imam intending the obligatory prayer first, because this is the natural order. So I do not know the validity of the question, but in any case, if he entered with him intending tarawih and then it became clear that the imam was praying the obligatory prayer, he continues with the imam, but this prayer does not suffice him for the obligatory prayer because he did not intend it. The Prophet (peace and blessings be upon him) said: This man was guided when he repeated the prayer afterwards, so he owes nothing after he repeated the prayer. Yes.