Hisham bin Urwah narrates from his father that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) recited the verse of prostration on the pulpit on Friday, then he came down from the pulpit and prostrated, and the people prostrated as well. Then on the following Friday he recited the verse of prostration on the pulpit, and the people got ready to prostrate. Sayyiduna Umar (may Allah be pleased with him) said: Stay in your places; Allah has not made it obligatory upon us, except if we wish. He recited the verse, did not prostrate himself, and also forbade the others from prostrating.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5796