"In the Bible the whole duty of man is defined. Solomon says, “Fear God, and keep his commandments: for this is the whole duty of man.” [ Ecclesiastes 12:13 .] The will of God is revealed in his written word, and this is the essential knowledge. Human wisdom, familiarity with the languages of different nations, is a help in the missionary work. An understanding of the customs of the people, of the location and time of events, is practical knowledge; for it aids in making the figures of the Bible clear, in bringing out the force of Christ's lessons; but it is not positively necessary to know these things. The way-faring man may find the pathway cast up for the ransomed to walk in, and there will be no excuse found for any one who perishes through misapprehension of the Scriptures. CE 84.1"
"Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man."
EGW directly quotes Ecclesiastes 12:13 and explicitly connects it to the 'whole duty of man'.
"In the Bible every vital principle is declared, every duty made plain, every obligation made evident. The whole duty of man is summed up by the Saviour. He says, “Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind.... Thou shalt love thy neighbor as thyself.” [ Matthew 13:37, 39 .] In the word the plan of salvation is plainly delineated. The gift of eternal life is promised on condition of saving faith in Christ. The drawing power of the Holy Spirit is pointed out as an agent in the work of man's salvation. The rewards of the faithful, the punishment of the guilty, are all laid out in clear lines. The Bible contains the science of salvation for all those who will hear and do the words of Christ. CE 84.2"
"Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind."
EGW directly quotes Matthew 22:37 and explicitly connects it to the 'whole duty of man'.