Another thought concerns the Keys of the church as well as the Great Commission.
Matthew 16:29: I will give you the keys of the kingdom of heaven; whatever you bind on earth will be
bound in heaven, and whatever you loose on earth will be[d] loosed in heaven.”
And then we have John 20:23: If you forgive the sins of any, their sins have been forgiven them; if you retain the sins of any, they have been retained
If you don't believe that Christ died for all, you cannot proclaim forgiveness as Christ instructs because you just aren't sure that that person has forgiveness. Then what does that mean? It means that you've lied to someone? Christ doesn't lead us to lie, but Satan does.
The Great Commission: Matthew 28:19-20:Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.
and Mark 16:15-16 And He said to them, "Go into all the world and preach the gospel to all creation. 16"He who has believed and has been baptized shall be saved; but he who has disbelieved shall be condemned.…
How do you go out and proclaim Christ's death for forgiveness if you don't believe he died for all? You don't really. You can only go out and proclaim his death and then they have to believe and maybe they're just lucky to get saved? Again, it's not Christ's plan to deceive people.
Christ died for all. He tells us in scripture to go out and proclaim this. That is the pure sweetness of the Gospel. The assurance we have and that our faith latches so we can believe.