From Sahih Muslim (Hadith 6751):
Abdullah b. Amr b. al-'As reported that he heard Allah's Messenger (ﷺ) as saying:Verily, the hearts of all the sons of Adam are between the two fingers out of the fingers of the Compassionate Lord as one heart. He turns that to any (direction) He likes. Then Allahs Messenger (ﷺ) said: 0 Allah, the Turner of the hearts, turn our hearts to Thine obedience
Reference: Muslim 6751