Musnad Ahmad 321:1

Waki’ narrated to us, he said: Al-A’mash narrated to us, from Abu Salih, from some of the companions of the Prophet, may God bless him and grant him peace, from the Prophet, may God bless him and grant him peace, who said: "The best of speech is: Glory be to God (Subhan Allah), and praise be to God (Al-hamdu lillah), and there is no god but God (La ilaha illa Allah), and God is the Greatest (Allahu Akbar)."