Sayyiduna Qays bin Asim (may Allah be pleased with him) asked the Prophet (peace and blessings be upon him) about alliances (pacts and covenants), and he (peace and blessings be upon him) said: "Whatever alliance there was in the Days of Ignorance, hold fast to it; and there is no new alliance in Islam."
Hadith Referenceالمعجم الكبير للطبراني / باب القاف / 15955