In any religious community that has an articulated creed, the first words uttered when the creed is recited are "I believe." The various things thereupon recited are the articles of religious faith. That is the primary meaning of the word "belief." It stands for things affirmed that lie beyond all philosophical knowledge or opinion, as well as beyond science and history.
The demonstrations of God's existence, if it is valid philosophical knowledge, is said to be a preamble to faith rather than an article of faith. In the three great religions of the West -- Judaism, Christianity, and Islam -- the first article of faith is that sacred scripture is the revealed word of God.
There are, of course, beliefs that are not religious faith. William James tells us about things he cannot affirm as knowledge but which he does affirm by exercising his will to believe. Unable to resolve the issue about the freedom of the will, a matter that troubled him greatly. He derived great comfort from willfully believing that human beings had freedom of choice.
To affirm this freedom, in his view was beyond all evidence and reason. Others similarly settle for belief in God, or in the immortality of the soul, by exercising what James called the will to believe. Such affirmation tend to be stronger and firmer convictions than the knowledge we have or the opinions we hold by empirical evidence and rational argument.
The element that is common to religious faith and nonreligious belief is its voluntary aspect. Both involve an exercise of the will. Being willing to believe is what distinguishes both religious and nonreligious faith from knowledge and right opinion. The will moves the reason to affirm what reason cannot establish by its own power. (See Knowledge and Opinion).
When religious faith is though of as divine gift, the will is moved by God to affirm what lies beyond the natural powers of the mind to acknowledge. The will is supernaturally moved for those who have a faith that is not religious, the factors that move the will are natural, not supernatural.