Sunan Abi Dawud Book 2, Hadith 184
The Messenger of Allah (ﷺ) saw a person praying alone. He said: Is there any man who may do good with this (man) and pray along with him.
Come to prayer with calmness and tranquility. Then pray the part you get (long with the imam) and complete afterwards the part you miss.
Abu Dawud said: Ibn Sirin narrated from Abu Hurairah the words: "he should complete it afterwards." Similarly, Abu Rafi' narrated from Abu Hurairah and Abu Dharr narrated from him the words "then complete it, and complete it afterwards." There is a variation of words in the narration from him.
Yazid prayed along with the Messenger of Allah (ﷺ) when he was a young boy. When he (the Prophet) had prayed there were two persons (sitting) in the corner of the mosque; they did not pray (along with the Prophet). He called for them. They were brought trembling (before him). He asked: What prevented you from praying along with us? They replied: We have already prayed in our houses. He said: Do not do so. If any of you prays in his house and finds that the imam has not prayed, he should pray along with him; and that will be a supererogatory prayer for him.