Mishkat al-Masabih 1228
Abu Sa'id al-Khudri reported God’s Messenger as saying, “There are three on whom God looks with pleasure:
a man when he gets up at night and prays, a company when they draw up in rows in prayer, and a company when they draw up in ranks to fight the enemy." 

[Baghawi] transmitted it in Sharh as-sunna .
وَعَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: " ثَلَاثَةٌ يَضْحَكُ اللَّهُ إِلَيْهِمْ الرَّجُلُ إِذَا قَامَ بِاللَّيْلِ يُصَلِّي وَالْقَوْمُ إِذَا صَفُّوا فِي الصَّلَاةِ وَالْقَوْمُ إِذَا صَفُّوا فِي قِتَالِ الْعَدُوِّ. رَوَاهُ فِي شَرْحِ السّنة