Yet there are some of you who do not believe. For Jesus had known from the beginning which of then did not believe and who would betray him. He went on to say, "This is why I told you that no-one can come to me unless the Father has enabled him."
This alone should put a stop to the idea of universalism - that all will be saved. Sadly, it is exactly the other way round - all are doomed - unless they become special cases. Salvation is all of grace. No-one comes to God unless the Father draws him. Our nature is to be rebellious; God's nature is to be forgiving, but he will not impose his nature on ours. For some of us, we will not believe and we will betray him.