Upvote:1
Whoever named the tune for the hymn "KENOSIS" (see bottom right corner here), made a theological opinion that this hymn is about Kenosis, recalling a hymn embedded in Phil 2:6-11, esp. verse 7:
Instead he emptied himself by assuming the form of a servant, taking on the likeness of humanity.
Therefore, reading your hymn, Jesus ("I", "me") is speaking to us ("thee", "thou") in the voice of the 2nd person of the Trinity before he was incarnated, sharing the throne of His Father since before the creation of the world. Second stanza:
My Father's house of light, My glory circled throne,
I left, for earthly night, For wand'rings sad and lone;
I left, I left it all for thee, Hast thou left aught for Me?
I left, I left it all for thee, Hast thou left aught for Me?
So in my opinion, this is a perfectly orthodox Trinitarian position. And as you surmised, this is describing God the Son leaving His previous glory by coming to the earth ("for earthly night" referring to the "silent night" of Christmas eve). I think we should not expand the meaning of the hymn to Jesus's ascension and second coming. Rather, the focus of the hymn is our proper response to Jesus (as God the Son) humbling himself on the cross of shame to give us forgiveness and salvation.
In addition, there are many other Bible verses that the lyrics alluded to:
The hymn text is by Frances Ridley Havergal, a 19th century Anglican. According to Wikipedia
Her religious views and theological bias were distinctly set forth in her poems, and may be described as mildly Calvinistic, without the severe dogmatic tenet of reprobation. The burden of her writings was a free and full salvation, through the Redeemer's merits, for every sinner who will receive it, and her life was devoted to the proclamation of this truth by personal labours, literary efforts, and earnest interest in Foreign Missions.