It was narrated from 'Abdullah bin 'Abbas that:He saw 'Abdullah bin Al-Harith praying with his hair bound behind him. He stopped and started to undo it. When he finished he turned to Ibn 'Abbas and said: "What were you doing to my head?" He said: "I heard the Messenger of Allah (ﷺ) say: 'The likeness of this is that of one who prays with his hands tie behind his neck

English translation · Sunan an-Nasa'i