What should one do if they enter the mosque and Maghrib prayer has begun, but they have not yet prayed Asr? Should they pray Asr after Maghrib, or Maghrib first, or Asr then Maghrib, or join the Imam in Maghrib and complete a fourth unit with the intention of Asr?

Whoever missed the Asr prayer and caught a congregation praying Maghrib, should pray with them with the intention of Asr, and add a fourth rak'ah after the Imam's taslim to complete the Asr prayer. Then, he should pray Maghrib after that. However, if he can pray Asr before the Maghrib prayer is established, he should pray it first, then pray Maghrib with the congregation. The order between prayers is obligatory, and Maghrib should not be offered before Asr.