Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) reports: The Prophet (peace and blessings be upon him) said: "Whoever's mawla I am, Ali too is his mawla. O Allah, love whoever loves him and be hostile to whoever is hostile to him."
Al-Tabarani recorded it. Its chain contains Umar bin Shabib al-Musallimi, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 14618