“Certainly the supreme goal in religion is that we shall serve God without coercion and fear, motivated only by love, in accordance with our natural inclination. In revelation it is God’s own purpose to mold people in whom his image is again fully restored. He gave us not only his Son but also the Holy Spirit in order that the Spirit should regenerate us, write his law in our hearts, and equip us for every good work. regeneration, adoption, sanctification, glorification–all proofs that God educates his children for freedom, for a ministry of love we will never regret.” Bavinck.
We can learn the purpose of something by looking at how it is made. A car has an engine. So it is usually suppose to do more than just sit in a parking lot for people to look at. Our salvation includes things like regeneration, adoption, sanctification, glorification. This tells us something of the purpose of our salvation. It is not merely forgiveness of sins, but so that we can relate to God.