"His work there had continued some months before the Sermon on the Mount was given. The message He had proclaimed throughout the land, “The kingdom of heaven is at hand” ( Matthew 4:17 ), had arrested the attention of all classes, and had still further fanned the flame of their ambitious hopes. The fame of the new Teacher had spread beyond the limits of Palestine, and, notwithstanding the attitude of the hierarchy, the feeling was widespread that this might be the hoped-for Deliverer. Great multitudes thronged the steps of Jesus, and the popular enthusiasm ran high. MB 2.2"
"From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand."
Ellen White directly references Matthew 4:17 in this passage.