God chooses [elects] individuals during their lifetime for salvation by transferring them spiritually into Christ based on crediting their faith as righteousness. Thus a conditional election, not unconditional. 2 Thessalonians 2:13
In order to understand the biblical mandate for individual election during our lifetime, you must consider 1 Peter 2:9-10 which says once we were not a people chosen for God's own possession. Once we had not received mercy, so we had to be chosen after we existed, thus during our lifetime. Foreseen this and foreseen that is precluded by the passage.
Next, you must understand Ephesians 1:4, which teaches God chose us in Him before the foundation of the world. If that election cannot be individual, then it must be corporate, God chose a type of individual as the target group of His redemption plan. When He chose His Redeemer individually, He necessarily chose corporately the believers Christ would redeem. Thus He chose us, those redeemed during our lifetime, corporately when He chose His Redeemer before creation.
I am addressing what I have underlined for edification purposes only.
Peter is wring his epistle to the strangers who are in the region we now know as Asia Minor. It was not just to strangers, generic, to whom he wrote, but to THE strangers in that region. These were strangers because they were of the "circumcision" who for the past 700 years were dispersed out of their own land in northern Palestine because of the judgement of God and for his eternal purposes. They were not going to be estranged from God forever but they would not be reclaimed nationally until every one of them were saved and were called "children of God." Until then, they were cut off from the national covenants of Israel, the people of God and considered by God as gentiles, being under the physical rule of the gentiles and partakers of many of their customs. These are the same people and gentiles of Romans 9.
The Judean Jews were a hindrance to these people and attempted to impose the Jewish laws on those who became Christians, which was anathema to both God and Paul, who wrote the epistle to the churches of Galatia where much of their activities were centered. There were real gentiles there as well and they too was led astray by these Judaizers.
Now, there is a body of study in the scriptures for what I am saying here and the Jewish Christian epistles is a dangerous place to build ones church doctrine on because Peter is emphasizing national and family promises in the context of the church of Jesus Christ.
I will give a couple verses to be pondered in this context.
1 Peter 2:9
But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light;
No one in that day and age would have agreed that they were a nation at that time in history and it was not the intent of Peter to have them believe they were. Why? Because he called them "strangers." The church is not a nation, but at some point these people will be and as God sees them they are.
The Ephesian church was in this same area and here is what Paul said to them that he never said to a European church group.
11 Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands;
12 That
at that time ye were without Christ, being
aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
13
But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
One should study the division of the Nation of Israel into two nations and consider the prophecies to each. I encourage the reading of the prophet Hosea who was contemporary with Isaiah, who addressed his prophecy to Jerusalem and Judah.
Here is an excerpt from Hosea to these people that Peter is addressing.
6 And she conceived again, and bare a daughter. And God said unto him, Call her name Loruhamah:
for I will no more have mercy upon the house of Israel; but I will utterly take them away.
7 But I will have mercy upon the house of Judah, and will save them by the Lord their God, and will not save them by bow, nor by sword, nor by battle, by horses, nor by horsemen.
8 Now when she had weaned Loruhamah, she conceived, and bare a son.
9 Then said God, Call his name Loammi: for ye are not my people, and I will not be your God.
10 Yet the number of the children of Israel shall be as the sand of the sea, which cannot be measured nor numbered; and it shall come to pass, that in the place where it was said unto them,
Ye are not my people, there it shall be said unto them, Ye are the sons of the living God.
11 Then shall the children of Judah and the children of Israel be gathered together, and appoint themselves one head, and they shall come up out of the land: for great shall be the day of Jezreel.
These are those to whom Paul referred in Romans about having no mercy, and God did not until Jesus came and now every one who is born again is called a son of God.