Does one who prayed the obligatory prayer alone and then found a congregation repeat the prayer?

Question:
Your Eminence the Shaykh, the questioner says: If I come to a congregation at a rest stop. Yes. If I come to a congregation at their rest stop, and I have already prayed the obligatory prayer, and they have not prayed yet, is it obligatory for me to pray with them, or is it recommended? May Allah reward you with good.

Answer:
If you have prayed in a mosque and then come to a group of people who are about to pray, pray with them, for it will be a voluntary prayer for you. As the Prophet (peace and blessings be upon him) said when asked about a woman who is delayed in her prayer: "Pray the prayer at its time. If the iqamah is called and you are in the mosque, pray with them, for it will be a voluntary prayer for you. Do not say, 'You have already prayed, so I will not pray.' If a person finds people praying, he prays with them, and it becomes a voluntary prayer for him. He shares in the good, even if it is in a time of prohibition, even if it is 'Asr or Fajr. Yes.