The Messenger of Allah ﷺ said, "No man who believes in Allah and the Last Day hates the Ansar. Were it not for the emigration, I would have been one of the Ansar myself, and if the Ansar took to a valley or a mountain pass, I would take to their valley or their pass. The Ansar are my inner garment, and the rest of the people my outer cloak."
وإن رسول الله ﷺ قال لا يبغض الأنصار رجل يؤمن بالله واليوم الآخر ولولا الهجرة لكنت امرأ من الأنصار ولو سلكت الأنصار واديا أو شعبا لسلكت واديهم أو شعبهم الأنصار شعاري والناس دثاري
Its isnad is sahih. Muslim narrated it in 1/86, no. 76, in the Book of Faith, evidence that love for the Ansar and Ali is part of faith, and Tirmidhi narrated it in 5/715, no. 3906, in the Book of Virtues, on the virtue of the Ansar, and he said, hasan sahih.