If anything, Satan loves this kind of ecumenical stuff. The scripture warns against welcoming heretics, or joining hands with unbelievers. There is no role that Jews and Christians play together to "redeem the world." Outside of Christ, there is no redemption!
Jesus is one facet of God. Salvation has always existed with God before God personified His salvation. People in the past before Jesus's coming looked forward to God's salvation just as we look back to it.
2 Samuel 22:3 "The God of my rock; in him will I trust: he is my shield, and the horn of my salvation, my high tower, and my refuge, my savior..."
2 Samuel 22: 47 "The Lord liveth; and blessed be my rock; and exalted be the God of the rock of my salvation."
Psalm 3:8 "Salvation belongeth unto the Lord: thy blessing is upon thy people. Selah."
Psalm 27:1 "The Lord is my light and my salvation; whom shall I fear? the Lord is the strength of my life; of whom shall I be afraid?"