Sayyiduna Ibn Abbas (may Allah be pleased with them both) said concerning this statement of Allah Almighty: "And they prevent (people) from it and keep away from it themselves" [Al-An'am: 26]: This was revealed about Abu Talib; he used to prevent (people) from harming the Prophet (peace and blessings be upon him), but himself kept away from following him (peace and blessings be upon him).
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12628