“Listen to Me, O Jacob, and Israel, whom I called;
I am He, I am the First, I am the Last.
“My hand founded and established the earth,
And My right hand spread out the heavens;
When I call to them, they stand together [in obedience to carry out My decrees].
“Assemble, all of you, and listen!
Who among them [the idols and Chaldean astrologers] has declared these things?
The Lord loves him (Cyrus of Persia); he will do His pleasure and purpose against Babylon,
And his arm will be against the Chaldeans [who reign in Babylon].
“I, even I, have spoken; indeed, I have called Cyrus;
I have brought him, and will make his way successful.
“Come near to Me, listen to this:
From the beginning I have not spoken in secret,
From the time that it happened, I was there.
And now the Lord God has sent Me, and His [Holy] Spirit.” – Isaiah 48:12-16
The Holy Spirit qualifies for service; and those may speak boldly, whom God and his Spirit send. This is to be applied to Christ. He was sent, and he had the Spirit without measure. – Matthew Henry
“Who is it that saith in Isaiah, And now the Lord hath sent me and his Spirit? in which, as the expression is ambiguous, is it the Father and the Holy Spirit who have sent Jesus; or the Father, who hath sent both Christ and the Holy Spirit. The latter is the true interpretation.” – Origen cont. Cels. lib. 1.
In the fulness of time, in the likeness of sinful flesh, to preach the Gospel, fulfil the law, and to redeem and save the Lord’s people. Here is a glorious testimony of a trinity of Persons in the Godhead; Christ the Son of God is sent in human nature,and as Mediator Jehovah the Father and the Spirit are the senders of him; and so is a proof of the mission, commission, and authority of Christ, who came not of himself, but was sent of God, (John 8:42), it may be rendered, “and now the Lord God hath sent me and his Spirit”; both were sent of God, and in this order; first, Christ, to be the Redeemer and Saviour; and then the Spirit, to be the Convincer and Comforter – John Gill
The Father and the Son have sent their Holy Spirit to bring this salvation to humanity. The Holy Spirit brings God’s Word to people. Through that Word, He opens their eyes to see their hopelessly sinful condition. He offers them peace through forgiveness for all of their sins in Jesus. He leads them to accept that forgiveness through faith in Jesus which He gives them. Through this faith in Jesus as their Savior, they are part of God’s eternal inheritance. They’re assured of life everlasting in the presence of the Triune God, Father, Son and Holy Spirit. Our Triune God’s work of salvation is complete – the LORD has redeemed His servant!