Sufyan bin 'Abdullah (May Allah be pleased with him) reported:
I asked: "O Messenger of Allah! Tell me, of something to which I may remain steadfast." He (ﷺ) said, "Say: My Rubb is Allah and then remain steadfast." Then I said: "O Messenger of Allah! What do you fear most about me?" He took hold of his own tongue and said: "This."[At-Tirmidhi]. (FR)
App reference (FR): Book 18, Hadith 7 (FR)
Arabic/English book reference (FR): Book 18, Hadith 1517 (FR)