Ali ibn Muhammad has narrated from Sahl ibn Ziyad from Ibn Mahbub from those he mentioned from abu 'Abdallah (a.s.) who has said the following.
"A man said, Allahu Akbar (Allah is Greatest) in his presence." The Imam asked, "Allah is Greatest than who?" The man replied, "Greatest than everything." The Imam said, "You have considered Him limited." The man asked, "Then, how should I say it?" The Imam replied
"Say, 'Allah is Greatest beyond description.'"ussol e kafi, H 316, Ch. 16, h 7