It is said that God uses analogies and parables in teaching mankind. In the year 1838, God was said to have descended from Heaven upon a small farming town in Japan, to save mankind. In teaching the early followers, God used words that were familiar with the agrarian community. The following is from the Book of Prophecy (Fudesaki) on why God descended from Heaven.
First to help those who grow crops,
I desired to teach you on the matter of the fertilizer.
Do not wonder why the fertilizer is effective.
If only God accepts your mind. 13-61
If one were to take these verses literally, one would believe that God was talking about agriculture, and how to increase the production of crops. But God is talking about how to increase church members. Crops refer to new members. Weeding refers to purifying the mind of evil (greed, arrogance, and self love). The fertilizer refers to a special prayer (Joyous Service) that God has given us to save all mankind. God is telling us that by performing and spreading the Joyous Service with a pure mind, it will bring forth new members to our churches.
Prayer (Joyous Service) + Pure mind = New Members
Why is the weeding of our minds so important for our prayers to be successful? Without a pure mind, how do we teach and help others when God brings them to our churches? This is why without a pure mind our special prayer is not receptive to God. This is why church membership does not increase. We must weed and use the correct fertilizer to harvest a large crop. Now we know why church membership does not increase. This information is all in the Book of Prophecy (Fudesaki).