"Among the Jews are some who, like Saul of Tarsus, are mighty in the Scriptures, and these will proclaim with wonderful power the immutability of the law of God. The God of Israel will bring this to pass in our day. His arm is not shortened that it cannot save. As His servants labor in faith for those who have long been neglected and despised, His salvation will be revealed. GW 399.1"
"Behold, the Lord’s hand is not shortened, that it cannot save; neither his ear heavy, that it cannot hear:"
The EGW passage directly alludes to Isaiah 59:1, referencing the Lord's arm not being shortened. The context of God's power to save is also consistent.
"And straightway he preached Christ in the synagogues, that he is the Son of God."
Both passages highlight the powerful preaching of converted Jews, exemplified by Saul/Paul.
"“Thus saith the Lord, who redeemed Abraham, concerning the house of Jacob, Jacob shall not now be ashamed, neither shall his face now wax pale. But when he seeth his children, the work of Mine hands, in the midst of him, they shall sanctify My name, and sanctify the Holy One of Jacob, and shall fear the God of Israel. They also that erred in spirit shall come to understanding, and they that murmured shall learn doctrine.” [ Isaiah 29:22-24 .]— The Acts of the Apostles, 379-382 . GW 399.2"
"Therefore thus saith the Lord, who redeemed Abraham, concerning the house of Jacob, Jacob shall not now be ashamed, neither shall his face now wax pale. But when he seeth his children, the work of mine hands, in the midst of him, they shall sanctify my name, and sanctify the Holy One of Jacob, and shall fear the God of Israel. They also that erred in spirit shall come to understanding, and they that murmured shall learn doctrine."
Ellen White directly references Isaiah 29:22-24 in this passage.