سنن أبي داود

A man from Banu Asad b. Khuzaimah asked Abu Ayyub al-Ansari: if one of us prays in his house, then comes to the mosque and finds that the iqamah is being called, and if I pray along with them ( in congregation), I feel something inside about it. Abu Ayyub replied: We asked the Prophet (ﷺ) about it. He said: That is a share from the spoils received by the warriors (i.e. he will receive double the reward of the prayer).