Forbearance is an interesting word and one we seldom use. It means to “patiently endure” but it is far deeper (and far more cool) than what those words explain.
The question Paul poses is, on a timeline, there have been a whole lot of people who have been born, lived, sinned and died, prior to Jesus; What about them? If God is fair and just, shouldn’t they have received the wrath that was due them? Did they get a “free pass”? If so, how is that considered right? Shouldn’t we all get a free pass, then? And, if there are “free passes”, why do we need Jesus?
Fortunately, Paul also answers the questions he poses for us in the book of Romans!
God did not give a “free pass”. God did not excuse their sin. That would be unjust and God is Just.
Instead, God “forbore” it. “For” (as in before) God “bore” (as in carried, like carrying the debt of another or carrying the burden of another) the just outcome of sin “for” (as in on behalf of) us. He patiently endured (forbearance) the weight of our injustice, until it, along with all the other sins and injustices of all people and all times (past, present and future) were laid on Jesus who “bore” them on the cross, “for” us so that we might be “forgiven” and thus “given” a new choice, as Adam and Eve were given choice, to accept or reject the gift of His payment “for” our sin. (I always joked that Paul was the master of run-on sentences and now he has me doing them, too!)
He had left things “un-right” i.e., He had not delivered the just punishment to mankind but had held it back so that Jesus could make the all-redeeming sacrifice that would resolve the earned punishment
By whole-heartedly putting my trust and faith in Jesus Christ and offering the life He has given to me as a tool for Him to use to spread the good news and help and support His bride, the church.