Whom God foreknew are all his people in Christ. God foreknew us as justified and glorified in Christ. God foreknew your salvation as complete (Philippians 1:6). In Romans 8:28-30, God's purpose in salvation is a prolepsis (i.e., to see before). God foreknew all who shall be in Christ (1 Peter 1:2).
Whom God foreknew are in Christ. All are commanded to repent and believe the gospel (Luke 13:3, 5; Acts 16:31). The gospel of Christ is offered to all. However, only those who repent and believe on the Lord Jesus Christ will be saved. As believers, we experience the gospel in power with assurance. That is the Holy Spirit working in us (1 Thessalonians 1:5).
Whom God foreknew are justified by grace through faith in Christ. Believers are justified through the death of Jesus Christ for our sins. Justification is by faith in the power of his resurrection. Justification means all our sins are taken away through the blood of Jesus (1 John 1:7). God declares we are justified by faith in Christ. "It is God who justifies" (Romans 8:33).
Whom God foreknew are glorified in the image or likeness of Christ. Glorification is our salvation complete. We shall be like Him, for we shall see Him as He is (1 John 3:2). What is future for us as believers is now in the foreknowledge of God. Therefore, whom God foreknew are glorified in the very image and likeness of our Lord Jesus Christ.