I heard the Messenger of Allah ﷺ say, "Allah has placed the truth upon Umar's tongue, and he speaks by it."
حدثنا أحمد بن يونس حدثنا زهير حدثنا محمد بن إسحق عن مكحول عن غضيف بن الحارث
سمعت رسول الله ﷺ يقول إن الله وضع الحق على لسان عمر يقول به
[Sahih] Reported by Ibn Majah, Introduction, chapter on the virtues of the companions of the Messenger of Allah ﷺ the virtue of Umar , hadith no. 108, from the hadith of Muhammad bin Ishaq, with this wording. Yaqub Farsi made explicit that he heard it directly, in his book Al-Marifa wal-Tarikh, 1/461. Hakim graded it sahih according to the standard of the two Shaykhs (Bukhari and Muslim), 3/87, and Dhahabi agreed with him. Ubada bin Nusai also narrated it from Ghudayf with this wording, Ahmad, 5/145. The hadith has very many corroborating narrations, see the previous hadith.