Assalam alaikum,
In Ayat 2 of Surat Fatiha of the Holy Qur'an (1:2), the opening chapter of the Holy Book, Allah [Exalted be His Name], says:--
"AL-HAMD LILLAHI RABB AL-ALAMIN" -meaning all Praise(s) be to Allah.
About this Noble Ayat, it is related that Ja'afar al-Sadiq, may Allah be Merciful to him, said, "He who praises Him [Allah] with His attributes, just as He has described Himself, has indeed praised Him, because praise [hamd] consists of a ha, a mim and a dal.
The ha comes from His Oneness (Wahdaniyya), the mim from His Kingdom (Mulk) and the dal from His Eternity (Daymumiyya). So whoever knows Allah Most High through His Oneness, Kingdom and Eternity, has indeed known Him.
A man said 'Praise be to Allah' in front of Junaid al-Baghdadi, so the latter said, 'complete it as Allah Most High says'; that is say 'the Lord of the Worlds'. The man replied, 'And what are the worlds that they should be mentioned alongside the Real?' Junaid replied, 'Oh my brother, say this for when originated things are associated with the Beginninglessly Eternal, not a trace of them remains.'
For further reading on this, see
"Haqa'iq al-Tafsir", by Abu Abd al-Rahman al-Sulami.