"As the children sang in the temple courts, “Hosanna; Blessed is He that cometh in the name of the Lord” ( Mark 11:9 ), so in these last days children's voices will be raised to give the last message of warning to a perishing world. When heavenly intelligences see that men are no longer permitted to present the truth, the Spirit of God will come upon the children, and they will do a work in the proclamation of the truth which the older workers cannot do because their way will be hedged up. CT 176.2"
"And they that went before, and they that followed, cried, saying, Hosanna; Blessed is he that cometh in the name of the Lord:"
Ellen White directly references Mark 11:9 in this passage.