Does Isaih 48:16 refer to Tri-Unity?

Isaiah 48:16—The Sovereign Lord has sent me, with his Spirit (cf. also perh. 61:1; also Zech 2:10–11). Here is the best candidate for explicitly Trinitarian language in the OT, but even this verse is not without tension. In addition to the problem of impersonal interpretations of spirit, we find that the speaker is not clearly defined. In the first three cola of the verse, God clearly is speaking. The fourth colon seems out of place and could be an anticipatory comment from the soon-to-be-revealed Servant-King, but this is dubious for its anachronism. More likely it is a timely assertion of Isaiah’s own prophetic authority.