What should a person do who arrives to pray with two individuals who are praying alone and are currently in the bowing position (rukūʿ)?

If one finds an Imam in rukoo’ (bowing) with only one other person, then he should say the takbeerat al-ihram (opening takbeer), then bow, and he should stand to the left of the Imam. If there is space in front of the Imam, then he (the Imam) should move forward, and the two persons should stand behind him. If there is no space, the two persons should move back behind him. If there is space in front of the Imam and behind the two persons, it is permissible for the Imam to move forward or for the two persons to move back, but the preferred (and correct) opinion is for them to move back and for the Imam to remain in his place.