Humran reported,

Ati reported that he saw Uthman bin Affan call for water for ablution. He poured water from the vessel over his hands and washed them three times. Then he dipped his right hand into the water, rinsed his mouth, drew water into his nose, and blew it out. He then washed his face three times, washed his arms up to the elbows three times, wiped his head, and washed each foot three times.Afterwards he said, "I saw the Prophet ﷺ perform ablution just as I have performed mine, and he said, 'Whoever performs ablution as I have done, then prays two units of prayer without letting his mind wander during them, Allah will forgive him his past sins.'"

Bukhari 164

Sahih

حدثنا أبو اليمان قال أخبرنا شعيب عن الزهري قال أخبرني عطاء بن يزيد

عن حمران مولى عثمان بن عفان

أنه رأى عثمان بن عفان دعا بوضوء فأفرغ على يديه من إنائه فغسلهما ثلاث مرات ثم أدخل يمينه في الوضوء ثم تمضمض واستنشق واستنثر ثم غسل وجهه ثلاثا ويديه إلى المرفقين ثلاثا ثم مسح برأسه ثم غسل كل رجل ثلاثا ثم قال رأيت النبي ﷺ يتوضأ نحو وضوئي هذا وقال من توضأ نحو وضوئي هذا ثم صلى ركعتين لا يحدث فيهما نفسه غفر الله له ما تقدم من ذنبه

البخاري 164صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Wudu
Chapter
Rinsing the mouth in wudu
Numbering
Darussalam 164
Bukhari 164