הַ֥לְלוּ יָ֨הּ ׀ הַֽלְל֣וּ אֶת־יְ֭הוָה מִן־הַשָּׁמַ֑יִם הַֽ֝לְל֗וּהוּ בַּמְּרוֹמִֽים׃
Hallelujah. Praise ye the LORD from the heavens; Praise Him in the heights.
Read kabbalistic (mystical) interpretation of Psalms 148:1: and classical mystical sources.