"There are very many who do not fear to deceive their fellow men, but they have been taught, and have been impressed by the Spirit of God, that it is a fearful thing to lie to their Maker. When put under oath they are made to feel that they are not testifying merely before men, but before God; that if they bear false witness, it is to Him who reads the heart and who knows the exact truth. The knowledge of the fearful judgments that have followed this sin has a restraining influence upon them. MB 67.1"
"Whiles it remained, was it not thine own? and after it was sold, was it not in thine own power? why hast thou conceived this thing in thine heart? thou hast not lied unto men, but unto God."
Both passages deal with the idea that lying to humans is also lying to God. While not a direct quote, the thematic connection is strong and relevant to the surrounding discussion.
"Jesus proceeded to lay down a principle that would make oath taking needless. He teaches that the exact truth should be the law of speech. “Let your speech be, Yea, yea; Nay, nay: and whatsoever is more than these is of the evil one.” R.V. MB 67.3"
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil."
EGW directly quotes Matthew 5:37 to support her point about truthful speech. The connection is undeniable.