"None need concern themselves about those things which the Lord has not revealed to us. In these days, speculation will abound, but God declares, “The secret things belong unto the Lord.” Deuteronomy 29:29 . The voice that spoke to Israel from Sinai is speaking in these last days to men and women, saying, “Thou shalt have no other gods before Me.” Exodus 20:3 . The law of God was written with His own finger on tables of stone, thus showing that it could never be changed or abrogated. It is to be preserved through the eternal ages, immutable as the principles of His government. Men have set their will against the will of God, but this cannot silence His words of wisdom and command, though they may set their speculative theories in opposition to the teachings of revelation, and exalt human wisdom above a plain “Thus saith the Lord.” CT 248.2"
"The secret things belong unto the Lord our God: but those things which are revealed belong unto us and to our children for ever, that we may do all the words of this law."
EGW directly quotes Deuteronomy 29:29.
"Thou shalt have no other gods before me."
EGW directly quotes Exodus 20:3.