God is a bit like the tide of the ocean. If you want to swim in the ocean it helps to know about tides, what and when they are. If you swim against the tide, you don't get much of anywhere. If you swim with the tide you get somewhere much more easily. Hopefully, that somewhere is your destination. You get to know God by experience, rather than by reading. You can read a little about tides to know that they exist and what they are, but until you try to swim, you don't know tides. Catechism is learning to swim, the technique. You can practice in a pool, or pond with smooth surface. Swimming in the ocean is like experiencing God. It is more than catechism which tells you there is such a thing as a tide and what it does. Many of us just read about stuff. We do not plunge in for the experience.