Did God Implement the Plan of Redemption the Day Adam Sinned?
Yes. Right on the same day man sinned, God implemented the plan of redemption devised before the beginning of time. This plan is revealed in the life, death, resurrection and high priestly ministry in the heavenly sanctuary of our Lord & Savior Jesus Christ. This is why Jesus is the Lamb SLAIN from the foundation of the world. God saved Adam in Christ the day he sinned and reinstated him to his pre-fall spiritual status. With Adam in Christ, all his descendants are born in Christ and therefore born spiritually alive instead of born spiritually dead in sin. Born spiritually alive being in Christ and part of His Body, they have His Power to overcome evil with good. And all overcomers will not be blotted out from the book of life but will be seated with Christ - Who Himself is also an overcomer - in His throne.
This, in a nutshell, is to my understanding, the gospel that Jesus wanted preached to the world just before He comes again. Matt 24:14.