Lutheran's Theology

I once had a very delightful conversation with a Lutheran. He told me that the Calvinist cannot have assurance. I told him the Bible seems to say so. He said no. Christ died for all men universally, he said. My response was - does that give you assurance? Maybe those who end up in hell did not have assurance? Regardless, assurance is not based on my belief but based upon the infallible promises of God. Perhaps maybe I cannot have assurance. The Gospel is not that Christ died for you. The Gospel is that Christ actually atoned for sins. The sins he atoned for are the Elect people of God. Without election, no one is atoned for.