I heard the Messenger of Allah ﷺ say, "Allah, the Mighty and Majestic, said, 'Who is more unjust than one who sets out to create something like My creation? Let them create an ant, or let them create a grain, or let them create a barley seed.'"
سمعت رسول الله ﷺ يقول: قال الله عزوجل: ومن أظلم ممن ذهب يخلق خلقا كخلقي؟ فليخلقوا ذرة أو ليخلقوا حبة أو ليخلقوا شعيرة.
Bukhari narrated it in the Book of Clothing (5953), and Muslim in the Book of Clothing (2111) - and this is his wording - both of them through the route of Umara, who said, Abu Zura told us, he said, I entered with Abu Hurairah into the house of Marwan, and he saw pictures in it, so he said, I heard the Messenger of Allah ﷺ say, and he mentioned it.