On the contrary, God forgiveness is free, but not cheap. There are certain things that God cannot do. One of those is that He cannot deny Himself (2 Timothy 2:13). He cannot justify the wicked.(Exodus 23:7 etc.). But on the cross,
'God made Him who knew no sin to be sin for us that we might become the righteousness of God in Him' (2 Corinthians 5:21). On the cross, all, the sins of God's people were laid upon Christ's sinless shoulders and His perfect righteousness credited to them (Isaiah 53:6).
I don't need to go anywhere near Ephesians. That the Father gave to the Son a people to redeem, of whom He will not lose one, is clear from John 6:40; 10:27-29; 17:2, 6.
In the providence of God, His people were given to Christ from eternity past. Christ is the Lamb slain from the foundation of the world. You need to understand that while God may do a new thing, He never makes a new plan, for if He did, the new one would be either better or worse than the old one, and God would either improve or decline, both of which are impossible (Malachi 3:6; Hebrews 13:8). All God's plans, therefore, are made in eternity, but come to fruition in time (c.f. 1 Peter 1:20; Titus 1:2).
God's plan of salvation was indeed made in eternity, but it came to fruition in time. Now, in Christ Jesus, I who was once far off have been brought near by the blood of Christ. Christ's blood availed for me because God gave me to Christ Jesus to redeem.
Before I was saved.
One of us does, but it isn't me.
Christians are not justified from eternity past-- we are justified when we repent and trust in Jesus. But we were given to Christ to redeem before time began (Jeremiah 31:3; Ephesians 1:4-5).