Ecclesiastes 10:18

By much slothfulness the building decayeth; and through idleness of the hands the house droppeth through.

Idleness causes the body to degenerate, just as neglect allows a building to decay and a house to leak through from lack of repair. Idle hands give opportunity for mischief to be brought in, while being kept busy in useful labor gives opportunity to be worked with for good. For students in school this means manual training work is to be maintained to keep them from evil and to help in the saving of souls.

The good influence of such labor overbalances its financial loss, even were that loss ten times as large as it is. The full number of souls thus saved from evil and won through busy, useful employment will be known only at the day of judgment.