The architect of treachery wanted Jesus to fail as Savior.
Satan’s goal hadn’t really changed since before he was cast out of heaven. Understanding Isaiah 14 to teach about Satan through the allegory of the King of Babylon, Satan made the same blunder he made before:
6 He who smote the people in wrath with a continual stroke, he that
ruled the nations in anger, is persecuted, and none hindereth. …
12
How art thou fallen from heaven, O Lucifer, son of the morning! how
art thou cut down to the ground, which didst weaken the nations!
13 For thou hast said in thine heart, I will ascend into heaven, I
will exalt my throne above the stars of God: I will sit also upon the
mount of the congregation, in the sides of the north:
14 I will ascend above the heights of the clouds; I will be like the
most High. …
27 For the Lord of hosts hath purposed, and who shall
disannul it? and his hand is stretched out, and who shall turn it
back?
Satan wanted to disannul God’s purposes and make Him fail in His word. Satan wanted to rule, to smite people down, he wanted the glory and the power, he wanted to be better than everyone else—and he thought he could outsmart God.
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Satan’s end-game
What ultimately was Satan hoping to accomplish through the betrayal of Judas, the envy of the Sanhedrin, and even the temporarily misplaced devotion of Peter? Luke understood:
And the people stood beholding. And the rulers also with them derided
him, saying, He saved others; let him save himself, if he be
Christ, the chosen of God. (Luke 23:35)
Talmage put it poignantly well:
The dominant note in all the railings and revilings, the ribaldry and
mockery, with which the patient and submissive Christ was assailed
while He hung, ‘lifted up’ as He had said He would be, was that awful
‘If’ hurled at Him by the devil’s emissaries in the time of mortal
agony; as in the season of the temptations immediately after His
baptism it had been most insidiously pressed upon Him by the devil
himself. That ‘If’ was Satan’s last shaft, keenly barbed and doubly
envenomed, and it sped as with the fierce hiss of a viper. Was it
possible in this the final and most dreadful stage of Christ’s
mission, to make Him doubt His divine Sonship, or, failing such, to
taunt or anger the dying Savior into the use of His superhuman powers
for personal relief or as an act of vengeance upon His tormentors? To
achieve such a victory was Satan’s desperate purpose. (Jesus the Christ pp. 658-659)
Satan wanted Jesus to be crucified so he could put Him in that terrible, tempting situation--in hopes of getting Him to do something that would disqualify Him from His perfect salvific role.
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Conclusion
Satan wanted to disrupt the plan of God by getting Jesus to fail in His mission. There was only one Christ (the Anointed One); there was no backup Savior. God gave His Only Begotten Son. The atonement of Christ was the showdown between the Greatest the Father sent and the worst Satan could muster. Satan was blinded by his arrogance then as he was before.
The Father allowed Jesus to be crucified because He was confident Jesus would succeed. Satan encouraged the crucifixion because He was confident Jesus would fail. As usual, the Father was right. God had Satan beat since before the foundation of the world.