"Satan knows that those who ask God for pardon and grace will obtain it; therefore he presents their sins before them to discourage them. Against those who are trying to obey God, he is constantly seeking occasion for complaint. Even their best and most acceptable service he seeks to make appear corrupt. By countless devices, the most subtle and the most cruel, he endeavors to secure their condemnation. PK 586.1"
"And he shewed me Joshua the high priest standing before the angel of the Lord, and Satan standing at his right hand to resist him."
Both passages depict Satan as actively opposing God's people. Zechariah 3:1 shows Satan resisting Joshua the high priest, while the EGW passage describes Satan's efforts to discourage and condemn those who are trying to obey God. The parallel lies in the shared theme of Satan's opposition to those who are faithful to God.
"Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:"
Both passages warn about the devil's activity against believers. 1 Peter 5:8 warns believers to be vigilant because the devil seeks to devour them. The EGW passage describes Satan's efforts to discourage and condemn those who are trying to obey God. The connection is the shared theme of Satan's active opposition to believers.
"In his own strength, man cannot meet the charges of the enemy. In sin-stained garments, confessing his guilt, he stands before God. But Jesus, our Advocate, presents an effectual plea in behalf of all who by repentance and faith have committed the keeping of their souls to Him. He pleads their cause, and by the mighty arguments of Calvary, vanquishes their accuser. His perfect obedience to God's law has given Him all power in heaven and in earth, and He claims from His Father mercy and reconciliation for guilty man. To the accuser of His people He declares: “The Lord rebuke thee, O Satan. These are the purchase of My blood, brands plucked from the burning.” And to those who rely on Him in faith, He gives the assurance, “Behold, I have caused thine iniquity to pass from thee, and I will clothe thee with change of raiment.” Zechariah 3:4 . PK 586.2"
"And he answered and spake unto those that stood before him, saying, Take away the filthy garments from him. And unto him he said, Behold, I have caused thine iniquity to pass from thee, and I will clothe thee with change of raiment."
Ellen White directly references Zechariah 3:4 in this passage.