Abdullah bin Amir bin Rabia reported,
Umar bin Khattab 
heard the voice of Ibn Mughtarif, or Ibn Gharf, the camel-driver singing in the depth of the night while we were traveling to Mecca. Umar urged his mount forward until he caught up with the group, and there he was with Abdul-Rahman.When dawn broke, Umar said, "Enough now. Be quiet now. Dawn has broken. Remember Allah."Then he noticed that Abdul-Rahman was wearing leather socks.Umar said, "Leather socks?"Abdul-Rahman replied, "I have worn them in the company of one better than you," or he said, "in the company of the Messenger of Allah ﷺ."Umar said, "I insist that you take them off, for I fear that people will look at you and follow your example."
Ahmad 1668
Daifحدثنا هاشم بن القاسم حدثنا شريك عن عاصم بن عبيد الله
عن عبد الله بن عامر بن ربيعة قال
سمع عمر بن الخطاب رضي الله عنه صوت ابن المغترف أو ابن الغرف الحادي في جوف الليل ونحن منطلقون إلى مكة فأوضع عمر راحلته حتى دخل مع القوم فإذا هو مع عبد الرحمن فلما طلع الفجر قال عمر هيء الآن اسكت الآن قد طلع الفجر اذكروا الله قال ثم أبصر على عبد الرحمن خفين قال وخفان فقال قد لبستهما مع من هو خير منك أو مع رسول الله ﷺ فقال عمر عزمت عليك إلا نزعتهما فإني أخاف أن ينظر الناس إليك فيقتدون بك
No references are available.
Its chain of transmission is daif, due to the weakness of Asim bin Abdullah bin Asim bin Umar bin Khattab. In manuscript H, it reads Asim bin Ubayd, which is an error.Ibn Mughtarif, or Ibn Gharf, I found no mention of him anywhere other than this place."Awdaa rahilatahu" means he made his mount go at a fast pace."Hayya", with fatha on the ha, sukun on the ya, and ending in a hamza, is an imperative expression meaning "be alert" and "wake up."A word with an addition found in manuscript K.In manuscript K it reads, "Fajr has already risen."In manuscript K it reads, "if you do not remove it," and in its margin there is another reading like the one given here. Its margin also contains the reading "so that they may follow you." I did not find this hadith in any of the references available to me.