Musnad Ahmad 1065:12

Yunus narrated to us, Layth narrated to us, from Yazid—meaning Ibn al-Had—from ‘Amr, from Mahmud ibn Labid, that the Messenger of Allah (ﷺ) said: "Indeed, the thing I fear most for you is the minor shirk (polytheism)." They said: "And what is the minor shirk, O Messenger of Allah?" He said: "Ar-Riya’ (showing off). Allah, the Mighty and Majestic, will say to them on the Day of Resurrection, when people are being recompensed for their deeds: 'Go to those whom you used to show off to in the world, and see if you find any reward with them.'"