This passage preceding your quote is particularly poignant (though he then himself actually proceeds with his trinitarian dogmatics)...
To answer your question about Luke 1, the kingdom can be forever even if he hands it back to his father. I'm not sure how I take the rule over the house of Jacob forever language, however. I'll have to look into that, but it strikes me as the sort of language frequently sounding unqualified but having assumed qualifications. Particularly, with a passage like this one in 1 Corinthians, something has to give, and I am not in the least persuaded by Lenski's attempts to qualify (or seemingly re-write) the 1 Corinthians passage.Lenski wrote:On the one hand, Paul's statement that "the Son himself" shall subject himself to God is used in proof of the subordination to the Father, which this destroys the equality of the three persons of the Godhead. On the other hand, we are told that it is not the business of exegesis to investigate whether Paul's statement agrees or disagrees with the Bible doctrine regarding the Holy Trinity. If this is not the business of exegesis, then exegesis has no business at all. If it cannot give a correct answer to this question of subordinationism, which involves the very doctrine regarding God himself, then all else it may attempt to give is valueless. Paul either does or does not teach the equality of the divine persons when he says that the Son will subject himself to the Father. Which is it? The answer must be exegetical and not dogmatical, for all true dogmatics rests wholly on true exegesis; it is wholly dependent and never independent.