After Adam had learned the names of all things, along with their properties and uses, Allah presented them to the angels and said: "Tell Me the names of these if you are truthful." Surah 2:31 The angels admitted their inability: "Glory be to You, we have no knowledge except what You have taught us. Verily, it is You, The All-Knowing, The All-Wise. " Surah 2:32
Allah Almighty then turned to Adam: "0 Adam! inform them of their names," and when he had informed them of their names, He said: "Did I not tell you that I know the Ghaib (unseen) in the heavens and the earth, and I know what you reveal and what you have been concealing?" Surah 2:33
Allah wanted the angels to know that He knew of their astonishment when He had told them about the creation of Adam and that He also knew of their confusion which they had not revealed, as well as what Iblis had concealed of his disobedience and ingratitude.