THE TRIBULUM
The Roman method of threshing grain has one man stirring up the sheaves while another man rides over it in a crude cart equipped with rollers instead of wheels (sometimes flat boards were used). Sharp stones or bits of iron were attached to the cylinders to help separate the husks from the grain. The cart was called a Tribulum. This is the origin of the word, "tribulation."
When afflictions come to us, we may think of ourselves as being torn into pieces under cruel pressures of adverse circumstances. Yet, the purpose of the Tribulum was not to tear up the sheaves, but to expose the grain. We are never put under the pressures of a trial needlessly.