The Purpose of the one true God, exalted be His glory, in revealing Himself unto men is to lay bare those gems that lie hidden within the mine of their true and inmost selves. That the divers communions of the earth, and the manifold systems of religious belief, should never be allowed to foster the feelings of animosity among men, is, in this Day, of the essence of the Faith of God and His Religion. These principles and laws, these firmly established and mighty systems, have proceeded from one Source, and are the rays of one Light. That they differ one from another is to be attributed to the varying requirements of the ages in which they were promulgated. — Gleanings from the Writings of Baha’u’llah, pp. 287-288.

Recently a reader of my essays brought me a couple of questions from a Christian friend that speak to the heart of Baha’i belief. Specifically, the questions focused on Baha’u’llah’s teaching that the Faith of God is revealed progressively and according to our capacity, in contrast to the prevalent Christian belief that Jesus is, for all time, the only source of God’s guidance.

The first question: If Baha’is believe in all these prior religions, how do you explain inconsistencies between them? They can’t all be true, can they?

The second question: Jesus told his followers several times that he was the only way to know God, so how can there be any other way?

I’m very familiar with these questions—because they’re the same ones I asked when I first heard of the Baha’i Faith. I was surprised as much by the answers as I was by where I found them: the Bible.

As a Christian I understood that what I called the Old Testament was the Tanakh of the Jewish faith. This scripture is composed of the Law (the Torah), the Prophets (Neviim) and the Writings (Ketuvim). The major Prophet of the Jewish faith is Moses. I also understood this: that though the Jewish theologians understood Jesus’ message to be in conflict with the faith taught by Moses, Jesus did not understand his faith in that way. Neither did I nor any other Christian that I knew. Rather, we believed that Jesus fulfilled Moses’ faith.

Jesus makes this claim, in fact: “Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfill.”— Matthew 5:17.

So, this raises a further question: Are Judaism and Christianity different faiths or are they different stages of the same faith?

At the very least, Christians agree that they are not in conflict—Moses is not false because Jesus is true and vice versa. But this raises another question: Why do they have different teachings? Why did Jesus uphold some things—the primary commandments to love God and our fellow human beings—and change others—the laws of divorce and the Sabbath?

This question doesn’t require interpretation; Jesus explains it in Matthew 19:7-9 when the Pharisees ask why Moses gave them a different law of divorce. He says: “Moses, because of the hardness of your hearts, permitted you to divorce your wives, but from the beginning it was not so.“

This is what Baha’u’llah means when he talks about progressive revelation. Moses taught one thing because of the hardness of the human heart (that is, its lack of spiritual capacity at the time); Jesus taught something different, not because God had changed, but because we had changed. Moreover, Jesus tells His own disciples that he has not given them complete knowledge, because they could not bear it. John 16:12-13 reads: “I still have many things to say to you, but you cannot bear them now. However, when He, the Spirit of truth, has come, He will guide you into all truth…”

Hence the Bible illustrates one faith, progressively revealed by Moses and Jesus—the anointed spokesmen of the same God. There is continuity: Moses taught certain things, some of which Christ continued to teach and some of which he changed. Christ withholds things that even his own disciples couldn’t understand, and promises another “Advocate” (the Spirit of Truth) would come to teach later.

This, in part, explains the differences between the faith as taught by Moses and the faith as taught by Jesus. They focus on different capacities and needs. In the same way that a human teacher would not teach a first grader and high school student the same things in the same way, so Moses and Christ taught their students differently. Baha’u’llah describes it this way:

The All-Knowing Physician hath His finger on the pulse of mankind. He perceiveth the disease, and prescribeth, in His unerring wisdom, the remedy. Every age hath its own problem, and every soul its particular aspiration. The remedy the world needeth in its present-day afflictions can never be the same as that which a subsequent age may require. Be anxiously concerned with the needs of the age ye live in, and center your deliberations on its exigencies and requirements. —Gleanings from the Writings of Baha’u’llah, p. 213.

Next: Understanding the Commandments of Men