Ibn Malik meant that whenever the Messenger of Allah ﷺ performed ablution, he would take a handful of water, place it beneath his chin, and run it through his beard, saying, "This is how my Lord commanded me."
حدثنا أبو توبة يعني الربيع بن نافع حدثنا أبو المليح عن الوليد بن زوران
يعني ابن مالك أن رسول الله ﷺ كان إذا توضأ أخذ كفا من ماء فأدخله تحت حنكه فخلل به لحيته وقال هكذا أمرني ربي عز وجل
[Its chain of transmission is daif]. Walid bin Zawran is lenient in narration, Taqrib: 7423. The hadith has a corroborating narration in Hakim: 1/149, no: 529, but its chain is also daif, since Zuhri narrated it with an ambiguous transmission (anana).