Shortening the prayer for the traveling imam is better than completing it

Q: A traveler catches up with the obligatory prayer while with residents, and he is the most deserving of leading them. Should he pray with them as a resident or as a traveler?

A: The Sunnah is that he prays with them as a traveler. When he concludes the prayer, they stand up and complete the prayer for themselves. This is because the Prophet (peace and blessings be upon him), when he prayed with the people of Makkah in the year of the Conquest, prayed with them as a traveler and ordered them to complete their prayer. If he completes the prayer with them, that is valid, but he has left the better option.
It is established from 'Umar (may Allah be pleased with him) that he would complete the prayer with the people during Hajj in the final years of his caliphate, and it is established from 'A'ishah (may Allah be pleased with her) that she would complete the prayer while traveling, saying: "It does not burden me, but the best is what the Prophet (peace and blessings be upon him) did, for he is the legislator who was taught by his Lord, the best of prayers and blessings upon him. And Allah grants success."