Maybe you’ve heard people talk about “the Trinity”—the Father, Son, and Holy Spirit (or Holy Ghost). Have you ever wondered what in the world that means?

Most people believe in some sort of deity.¹ Jews and Muslims are monotheists; they believe in only one, true God. Hindus, Buddhists, and adherents of most tribal religions put their faith in many different gods; they are polytheists.

But standing in the peculiar middle are Christians. For almost two thousand years, Christians have maintained that, yes, there is only one God, but he exists in three different persons: Father, Son, and Holy Spirit. Together, they form the Trinity.

How strange.

How does that work? Isn’t that more like believing in three gods, not one? And why do Christians believe in God as a Trinity in the first place?

The word “Trinity” doesn’t appear anywhere in the Bible. There are no biblical passages that explicitly explain God as a triune (three-in-one) being. Since Christianity derives its views about God from the Bible, this is odd. It all goes back to a simple question: What is the Trinity?

One True God

The Bible unequivocally asserts that there is only one God, upholding the monotheism of the ancient Israelites. They believed in only one God; all other idols, claims to deity, and so-called gods were deemed to be false.²

As devout Jews, early followers of Jesus—who eventually became known as Christians—professed their faith in one God as well.³ Later Christians even used philosophical categories from Greek thought to explain that God had only one nature, one substance, and one essence that is never divided.⁴

In other words, God is not schizophrenic. He does not change forms nor is he the head of a pantheon of gods. As Christians around the world continue to assert today: there is only one God.

God as Three-in-One

But something changed among those first followers of Jesus.

Even though they remained monotheists, they also regarded Jesus as God. They prayed prayers to him, sang hymns to him, and gathered in his name. They related to Jesus as one might relate to God. Because of Jesus’ astounding teachings, miracles, and resurrection, they became convinced that God had become a human being in the person of Jesus.

Yet Jesus still prayed to God as his Father. He talked and acted as if God was distinct from him. Jesus also spoke of another “Helper”: the Holy Spirit (a term sometimes found in the Old Testament to describe God). When Jesus left the earth, he said this Spirit would come and reside in the hearts of his followers, bearing God’s very real presence and leading them in truth and life.⁵

To cap it all off, Jesus gave his followers a mission just before he left. He challenged them to help others become believers as well. As a symbol of each changed life, he directed them to baptize those new followers in water “in the name of the Father and of the Son and of the Holy Spirit.”⁶ This three-fold formula became the key to the Christians understanding of who God is—one God, existing in three different persons.

Analogies of the Trinity

The idea of God as three-in-one is indeed a mysterious concept, one that is difficult to understand. Analogies often fall short.

Some think of God as H₂O, which is sometimes a solid (ice), sometimes a liquid (water), and sometimes a gas (steam). Others compare God to an egg, which is part shell, part white, part yolk.

The theologian Augustine offered a psychological analogy. He reflected on how the human mind has three faculties—memory, understanding, and will—but remains unified.⁷ Still others have suggested people as examples. For instance, a woman might have different roles in her life—an employee at work, a friend at the gym, and a wife at home—but she remains one person.

All of these analogies attempt to explain how one entity can constantly be three persons. You see, God—as Christians understand him—does not decide to be like a Father one day, like Jesus another day, and like a Spirit the next. He does not simply change roles or forms.

Rather, God is always one substance that is shared by three independent “persons” who each have a unique will and personality—and each is equally God. In fact, Christian teaching says that the Father is fully God, Jesus is fully God, and the Holy Spirit is fully God.⁸

Theologians have offered more sophisticated and philosophical ways to understand the Trinity.⁹ Some may wish to consider those explanations before they decide whether or not to believe them.

Others simply describe the Trinity as an incomprehensible mystery that cannot be fully understood. Logic is stretched to its extremes and human language is often inadequate. But, they claim, should we expect any different of a transcendent God that created the universe? If we could fully understand everything about him, would he really be a God worth worshiping?

Love Is at the Center

Perhaps the best explanation comes from a simple verse in the Bible: “God is love.”¹⁰ The term “love” is often associated with affections and emotions. But practically speaking, love requires a subject, an object, and an action—a person to do the loving, an object to receive the love, and the act of loving. For example, think about giving yourself and your love to someone else.

Genuine love cannot be expressed by yourself; it requires others to give yourself away to. Thus, God did not simply begin to experience “love” only after he created the world and humans (objects whom he could love). God is love.

As theologian Jonathan Edwards explained, “The very essence of God’s reality is the intratrinitarian love of the Father, Son, and Holy Spirit.”¹¹ His eternal existence is rooted in a shared love experienced within himself.

Furthermore, Edwards maintained that we are the beneficiaries: “The only possible reason for such a being to create the universe was to extend that love to other, imperfect, beings. . . . All created reality is like a quintessential explosion of light from the sun of God’s intratrinitarian love.”¹²