Silsilah as-Sahihah 1337 — Staying away from congregation and fighting

It is narrated from Sayyiduna Jundub bin Abdullah Bajali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever is killed blindly under a banner, where he called for tribalism or helped on the basis of tribalism, then his being killed will be like the killing of the days of ignorance."