Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) said: "There is no marriage without a guardian (wali)." (Imam Ibn Hibban, may Allah have mercy on him, says:) The narrator named Abu Burdah heard this narration from Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) as a marfu' (attributed to the Prophet) hadith, so once he narrated it from his father as a musnad (connected) narration, and once he narrated it as a "mursal" (disconnected) narration. Abu Ishaq heard this narration from Abu Burdah both as "mursal" and "musnad," so sometimes he narrates it from him as a "marfu'" hadith, and sometimes as a "mursal" hadith. So there is no doubt that this narration is authentic (i.e., reliable) both as "mursal" and "musnad." There is no doubt about its authenticity.