I disagree and feel that's a distortion of scripture. How do you figure that because He is called the Lamb slain from the foundation of the world that that means He is still being slain at the end of it? Just the opposite!
The crucifixion happened WITHIN our time. It is NOT a timeless act. Nothing in scripture indicates that it is. The only way that it could be occurring perpetually is if it happened in eternity, but it did not. The RESULT of Jesus' sacrifice is eternal, but the act itself is not occurring eternally. If it is, then it is NEVER FINISHED. And God says otherwise. Jesus SAT DOWN at the right hand of the Father. The High Priest finished His duties and sat down. And one day He'll stand up as the Lion of the Tribe of Judah.
If Christ's Sacrifice on the Cross is NOT a timeless act, if only the 'RESULT of Jesus' sacrifice is eternal, but the act itself is not occurring eternally,' the why is there an Altar in Heaven?(See, Rev. 6:9; 8:3-5; 9:13; 11:1; 14:18; and 16:7. Bearing in mind an altar is only necessary for offering of sacrifice.)