My doctrine - My teaching, or what I teach. This is the proper meaning of the word “doctrine.” It is what is taught us, and, as applied to religion, it is what is taught us by God in the Holy Scriptures.
Is not wine - It is not originated by me. Though I have not learned in your schools, yet you are not to infer that the doctrine which I teach is devised or invented by me. I teach nothing that is contrary to the will of God, and which he has not appointed me to teach.
His that sent me - God’s. It is such as he approves, and such as he has commissioned me to teach. The doctrine is divine in its origin and in its nature.