Last week, I took part in a Google Hangout at Ligonier's 2013 National Conference. One of the questions I was asked was, "How can I explain the Trinity to a small child without moralistic illustrations or logical arguments that go over their head?" You can watch the answer below at 11.10.
Having had a bit more time to think about this, I would now answer as follows:
1. Read the Bible with your children: We believe the Bible reveals and communicates the Trinity in the best way possible. Therefore, let's expose our children to the Bible and let the truth of the Triune God soak into them over the long-term. Via the Bible's stories, letters, songs, and dialogues, they will gradually absorb the truth that God is one, but exists in three persons.
2. Catechize your children: At the Ligonier conference, Sinclair Ferguson spoke of the need to add catechism instruction to consecutive Bible exposition. He said that catechism teaching is like Velcro strips that the Bible's teaching sticks to. So, add the shorter catechism to your Bible reading: "There are three persons in the Godhead, the Father, the Son, and the Holy Ghost; and these three are one God, the same in substance, equal in power and glory." We're not trying to explain that or get our children to understand it, but simply providing Velcro for the Bible's truth to stick to.
3. Encourage your children to experience the Trinity: One of the best arguments for the Trinity is Christian experience. Many Christians didn't understand the Trinity before they were converted, but once converted they started relating to God in each of His three persons, and they found "it works." Again, they may not be able to fully understand it or explain it, but it works itself out very naturally in the daily experience of the Christian. I encourage my children to speak to each of the three persons of the Trinity and to build a relationship with each of them together.
4. Focus your children on Christ: While I want my children to know God in each of His three persons, Jesus is the gateway into the Godhead. He is God's exegete, the one who explains and communicates God (John 1:18). As He is the only way to God, the more we know Christ, the more we will know His Father and His Spirit. I would especially focus attention on John's Gospel where Jesus speaks of His relationship to His Father and His Spirit in the most simple yet profound words.
5. Pray for your children: Without the illumination of the Holy Spirit they will never understand God. They need their eyes opened, their minds renewed, and their hearts changed. No amount of our instruction can substitute for that. And while you're at it, pray for faith to believe that God can teach our children the most complex truths far more effectively than we can.
6. Excite our children: By the way you talk about God, worship God, and serve God, communicate to your children just how wonderful God is and how much you enjoy knowing Him and loving Him. If we are passionate and enthusiastic about knowing God, our children will catch that from us and be motivated to seek Him for themselves.
