That Christ is very God is apparent in that Paul ascribes to Him divine powers equally with the Father, as for instance, the power to dispense grace and peace. This Jesus could not do unless He were God.
To bestow peace and grace lies in the province of God, who alone can create these blessings. The angels cannot. The apostles could only distribute these blessings by the preaching of the Gospel. In attributing to Christ the divine power of creating and giving grace, peace, everlasting life, righteousness, and forgiveness of sins, the conclusion is inevitable that Christ is truly God. Similarly, St. John concludes from the works attributed to the Father and the Son that they are divinely One. Hence, the gifts which we receive from the Father and from the Son are one and the same. Otherwise Paul should have written: Grace from God the Father, and peace from our Lord Jesus Christ. In combining them he ascribes them equally to the Father and the Son. I stress this on account of the many errors emanating from the sects.
The Arians were sharp fellows. Admitting that Christ had two natures, and that He is called very God of very God, they were yet able to deny His divinity. The Arians took Christ for a noble and perfect creature, superior even to the angels, because by Him God created heaven and earth. Mohammed also speaks highly of Christ. But all their praise is mere palaver to deceive men. Paul’s language is different. To paraphrase him: You are established in this belief that Christ is very God because He gives grace and peace, gifts which only God can create and bestow.
Martin Luther, Commentary on Galatians (Kindle Edition, location 171)