The separate personality and Divine authority of the Holy Spirit.
The doctrine of the Holy Trinity, like most of the other great and mysterious doctrines of true religion, was gradually revealed to mankind. In one sense we may call it an exclusively Christian doctrine; but in another we must assign it an antiquity far higher than that of the Christian era. God, in his several revelations to mankind, gradually paved the way for its acceptance. In the revelations which he made to Noah and Abraham (Genesis 9:6, Genesis 9:16; Genesis 17:7, Genesis 17:8), God announced himself as Elohim—a word of plural form. In the revelation which he caused to be put forth by his servant Moses, he distinguished between" God" (Elohim) and "the Spirit of God" (ruakh Elohim) which moved, or brooded, upon the face of the primeval chaos (Genesis 1:2). By David he made it known that there was a "God, whose "throne was for ever and ever," whom "God, even his God, would anoint with the oil of gladness above his fellows" (Psalms 45:6, Psalms 45:7; comp. Hebrews 1:8, Hebrews 1:9). To the same great saint he revealed it that his Holy Spirit could be given to man and taken from him (Psalms 51:11). Isaiah, in the present passage, proclaims that he is sent "by the Lord Jehovah".