"And He Himself is the propitiation for our sins, and not for ours only but also for the whole world" (1 John 2:2). Propitiation means the sacrifice of Christ satisfying God's righteous judgment of our sins. It is "for the whole world." That refers to the scope of all nations, Jews and Gentiles. It is not limited to the Jewish nation only, but includes the world of all nations (Rev. 5:9).
The propitiation of our Lord Jesus Christ satisfied the judgment of God's wrath against sinners who repent and come by faith to Christ. He is the substitute for every believer, taking our judgment and the curse of our sins at the cross (2 Corinthians 5:21).
The propitiation of Christ is unlimited in value and worth, but it is limited to save to the uttermost only those who believe. The gospel preacher must proclaim the death of Jesus Christ unlimited in its offer to all, and command all to believe in Him for the forgiveness of all their sins. Anything less is not preaching the gospel of Christ.
Jesus Christ died to save those who believe and receive (John 1:11-13). It is the testimony of saving grace in the heart of all those who truly believe on the Lord Jesus Christ (Acts 16:31; Romans 10:9). The testimony of every believer is "Christ died for me."