Sunan Abi Dawud Book 2, Hadith 183
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.
I heard the Messenger of Allah( may peace be upon him) say: When the iqamah is pronounced for prayer, do not come to it running, but come walking(slowly). You should observe tranquility. The part of the prayer you get(along with the imam) offer it, and the part you miss complete it(afterwards).
Abu Dawud said: The version narrated by al-Zubaidi, Ibn Abi Dhi’b, Ibrahim b. Sa’d, Ma’mar, Shu’aib b. Abi Hamzah on the authority of al-Zuhri has the words: “the part you miss then complete it”. Ibn ‘Uyainah alone narrated from al-Zuhri the words “then offer it afterwards”. And Muhammad b. ‘Amr narrated from Abu Salamah on the authority of Abu Hurairah, and Ja’far b. Rabi’ah narrated from al-A’raj on the authority of Abu Hurairah the words “then complete it”. And Ibn Mas’ud narrated from the Prophet(ﷺ) and Abu Qatadah and Anas reported from the Prophet( may peace be upon him) the words” then complete it”.
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.