Abu Uthman reported,

Umar wrote to us while we were in Adharbayjan, "Utba bin Farqad, this wealth is not from your own toil, nor from the toil of your father, nor from the toil of your mother. So feed the Muslims in their dwellings from the same food you eat in your own dwelling. Beware of luxury, the dress of the polytheists, and the wearing of silk, for the Messenger of Allah ﷺ forbade the wearing of silk, except this much." And the Messenger of Allah ﷺ raised for us his middle finger and index finger and held them together.Zuhayr said, Asim said, "This is what was in the letter."And Zuhayr raised his two fingers.

Muslim 5411

Sahih

حدثنا أحمد بن عبد الله بن يونس حدثنا زهير حدثنا عاصم الأحول

عن أبي عثمان قال

كتب إلينا عمر ونحن بأذربيجان يا عتبة بن فرقد إنه ليس من كدك ولا من كد أبيك ولا من كد أمك فأشبع المسلمين في رحالهم مما تشبع منه في رحلك وإياكم والتنعم وزي أهل الشرك ولبوس الحرير فإن رسول الله ﷺ نهى عن لبوس الحرير قال إلا هكذا ورفع لنا رسول الله ﷺ إصبعيه الوسطى والسبابة وضمهما قال زهير قال عاصم هذا في الكتاب قال ورفع زهير إصبعيه

مسلم 5411صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Clothing and adornment
Chapter
Prohibition of using gold and silver vessels for men and women, gold rings and silk for men, their permissibility for women, and permissibility of silk borders and the like for men as long as it does not exceed four fingers
Numbering
Darussalam 5411
Muslim 5411