6. Believing in God

It seems that if there is a God, you shouldn't have to be a philosophy professor or master logician (man of logic) to figure out that He exists. Nor should you have to be a debate champion in order to convince others that He exists. Add to this that many of the historical arguments for God's existence only assert probability. Are we to suppose that on judgment day God will judge the unbelievers by stating that they should have known that He probably existed? There is no explicit argument anywhere in the Bible for the existence of God. Again, why do you suppose that is?