We strongly discourage you from introducing the topic of the Trinity or God’s nature, even though it is popularly encouraged. Our main reason for doing so is that the LDS teaching about God is attractive to most Mormons. I recall a nice conversation with a young mother who had been raised in a very active Christian home but converted to Mormonism in her late teens. I asked her what attracted her to Mormonism. Without hesitation, she said that Mormonism made God understandable to her. Her answer didn’t surprise me. I expected it because many others from similar backgrounds had told me the same thing.
Our experience is that, before they know Jesus as their Savior, Mormons are confounded by the teaching of the Trinity and quickly reject it. Once they know Jesus as their Savior, however, they are much more inclined to seriously look at what the Bible says about God’s nature and accept it much more readily. As one analyzes its descriptions of the witnessing efforts of the early church, it quickly becomes evident that their focus was on the problem of human sin and God’s solution in the work of Jesus Christ. You will search in vain for examples of how to witness by talking about the Trinity. Such examples are just not there.
Sometimes, however, the missionaries will not only bring the subject up but emphasize it. They won’t let us ignore it. At such times, we are tempted to try to explain the Trinity, especially by using one of the many popular illustrations. However, no explanation or illustration of the Trinity is satisfactory since God’s triune nature is truly unfathomable to human reason.
Here is one of those places where it is often better to proclaim rather than to explain. Make no bones about how unfathomable God is. In fact, go out of your way to stress that we cannot understand his nature. Highlight God’s greatness, emphasizing he is a completely different being. In this connection, I like an illustration a friend shared with me. God is on a vertical plane, and we are on a horizontal one. Since we are on completely different planes, the only thing we can know of God is the point where those planes intersect. This point is equivalent to Jesus’ coming to earth and God’s revelation of himself in the Bible. However, this also means that the vast percentage of God’s nature and ways are unknowable to us.
Whether you find the illustration useful or not, realize the futility of trying to explain the Trinity. Instead of causing frustration over God’s unsearchable nature, model how to stand in awe of it. Talk about how you appreciate having a God you can’t understand because it emphasizes how great he is. Contrast this with the idea that if we could understand God, it would show he wasn’t very great. Express your gratitude that such an awesome God loved you enough to save you – at great cost to himself. And then talk again about what Jesus has done for us.