On our calling to be saints this was given to us (individual believers who have names) before time began that we would belong to Christ.
Our LORD has saved us according to His own purpose, and not because we said Jesus is LORD, those words we spoke are part of the conformational process of the work of God in our life, but not the origin of our salvation which clearly began with His plan for us. Our salvation to occur in the future time of our life on this earth was certain according to His predetermined plan, that is a very important observation here and the verse shows it to be true. That it says 'holy calling' means it is having to do with the plan of God for our being saved, not our decision was involved, we were not around when God figured all this out way back before time began. This was His choice.
1 Timothy 1
9 who has saved us and called us with a holy calling, not according to our works, but according to His own purpose and grace which was given to us in Christ Jesus before time began,
While we were still in our sins, Christ died for us (the forenamed called ones whom God called before time began to be His people) because of His love towards US. The truth that this refers to His elect called ones, is shown by the next verse, as only we are justified by His blood and saved from HIS wrath. If Christ had not died for US, then the plan of God could not happen according to His will. It is why Christ came, and why Christ said about going to the cross, saying, “Father, if it is Your will, take this cup away from Me; nevertheless not My will, but Yours, be done.”
Romans 5
7 For scarcely for a righteous man will one die; yet perhaps for a good man someone would even dare to die. 8 But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us. 9 Much more then, having now been justified by His blood, we shall be saved from wrath through Him.
And again we are taught in Ephesians 2, that God did this for us because of His love for us.
4 But God, who is rich in mercy, because of His great love with which He loved us, 5 even when we were dead in trespasses, made us alive together with Christ (by grace you have been saved), 6 and raised us up together, and made us sit together in the heavenly places in Christ Jesus, 7 that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus.
All of verse 8 here is the gift of God. Then verse 10 tells us He made us, this salvation process was all of Him, not of us, this is what these 3 verse are saying.
8 For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, 9 not of works, lest anyone should boast. 10 For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.
Regarding our salvation and what is the gift of God, it is our being born again according to the mercy and will of the Holy Spirit, it is His marvelous grace towards us, and it is our responding faith in Christ, all of these are intertwined, and cant be seperated one from the other. If God did not make us born again, we would not have faith, so all of them are gifts as our salvation depends on them together in sequence, like an order of salvation.
Everything is built upon a foundation, Christ said we must be born again, because the flesh profits nothing, meaning the flesh is worthless in understanding spiritual things of God like who Christ is. if the flesh had some worth regarding our believing in Christ, we would not need to be born again. And being born again means to become spiritually awakened to the kingdom of God
Our individual salvation was written down in His book from before the foundation of the earth.