Parable of the Combine
A kernel of wheat grows in a head with other kernels on a wheat stem or straw. It grows with its own husk, barb and beard called chaff. For each wheat to be useful and fulfil its purpose in life, it must first be separated from all chaff and straw.
As a boy I grew up in the rural Utah community of Flowell. My father was a farmer but his day job was General Manager of the Flowell Electric Association, the electric cooperative that provides electric power to the area. My grandfather still worked on the farm back then. I was blessed to spend a great deal of time farming with my grandfather. One of my favorite things to do was to go with him to help operate the combine while threshing wheat. We raised both dry land and irrigated wheat. After the harvest each year, he took me fly fishing on our favorite streams in the Beaver mountains to celebrate our accomplishment.
Combining grain is still one of my favorite farming operations. It is a challenge to do it well because combines have many operator settings for the many moving parts. It is a great feeling as clean grain pours into the bin on the combine, grain that moments before was a standing crop in the field of yellow dried stems with heads. I have thought about the combine recently and want to share the Parable of the Combine.
In the Parable, the combine operator is God. The crop is young men and women ready to serve missions. The header is the MTC. The thrashing process is your mission which includes the cylinder and concave with rasp bars which are the trials and adversity during your mission. The grain is you, the individual missionary. The chaff (husks, barbs and beards) and straw are the distractions, worldliness, sin, weaknesses, bad habits, etc. that missionaries bring to or acquire in the mission field.
As a missionary, you are a grain in a head of wheat including your straw and chaff which are impurities attached to you but are unwanted and need removal. You must pass between the cylinder and the concave in the threshing process. The cylinder is spinning at high speed with rough, abrasive rasp bars on both the cylinder and the stationary concave. It literally beats and tears the crop and removes all chaff from you, the bare wheat kernel. You fall through the sieves and are augured to the clean grain bin while the chaff is blown out the back with a fan. But some grain refuses to give up the chaff. Those heads are sent through the return augur back to the cylinder where they re-live the high speed beating and tearing. This cycle is repeated as many times as it takes until all chaff is removed from the grain. The combine operator sets the cylinder clearance and rotating speed just high enough so that if spun at a higher speed the kernels would crack.
I often wonder why some missionaries choose to continue going through the return augur to the cylinder and concave because they will not give up the chaff. Everyone comes here with weaknesses and imperfections. You make progress toward your potential as you consistently do your best while experiencing the opposition, trials and adversity associated with serving here. Some experiences are difficult, others are enjoyable. In all cases, you have a duty to continue picking yourself up and striving for excellence. This is not the time for you to accept your distractions, worldliness, sin and weaknesses as acceptable. It is not the time to quit. You will only be recycled through the cylinder. Take a lesson from Paul who taught with all confidence until the end even though his trials were much worse than yours.
When Paul journeyed to Jerusalem for the last time, he was persecuted, arrested and bound. His experience is a great demonstration of his resolve to do his best. It included physical persecution but is a great metaphor for you and your trials.
The Jews knew Paul and wanted him gone. When they saw him in the temple they took him out and set about to kill him by beating him. It was such a lopsided fight it seemed that all of Jerusalem was in an uproar against one; Paul. The chief captain did not know what was going on but took soldiers and centurions and ran to the commotion. When the Jews saw the soldiers they stopped the beating. So much tumult and shouting ensued that the soldiers bound Paul in chains and literally had to carry Paul to the castle because of his injuries from the violent beating by the people. (Acts 21:30-38)
So what does Paul do while being carried to the castle like that? He displayed a wonderful example of tenacity and willingness to give up his chaff as he strives for excellence in his ministry. Many of us, in a similar circumstance, would kick back, thinking we had done enough that day.
39 But Paul said…I beseech thee, suffer me to speak unto the people.
40 And when he had given him license, Paul stood on the stairs, and beckoned with the hand unto the people. And when there was made a great silence, he spake unto them in the Hebrew tongue, saying… (Acts 21:39-40)
He then gave one of the best sermons of his ministry, recounting the story of his conversion and seeing Jesus on the road to Damascus. You would do well to develop the same tenacity with your urge for excellence. This will facilitate your chaff and straw removal.
Technical Explanation of how a Combine Threshes:
For the record for those of you unaccustomed to the operation of a combine thresher, the following is a technical explanation. As the combine moves across the field, the crop is cut by the cutting bar in the header. The header reel pushes the cut shafts of grain with the heads still attached into the header. The rotating header auger moves the cut crop to the center of the header. From the center of the header, the cut crop is carried up the feeder throat or “feederhouse” by an elevator of chain and flights which feeds the crop into the threshing mechanism of the combine.
In the threshing mechanism, the crop first hits a threshing drum rotating at high speed, commonly called the "cylinder". The cylinder has grooved steel rasp bars bolted to it. The rasp bars thrash or separate the grains and chaff from the straw through the action of the cylinder against the stationary concave, a shaped half drum, also fitted with steel bars and a meshed grill, through which most grain, chaff and smaller debris fall. The cylinder speed is adjustable and the distance between the cylinder and concave is finely adjustable to achieve optimum separation of grain from chaff and thrashing output without cracking the grain. The straw, being long, is carried past the cylinder onto the straw walkers. The straw walkers are located along the top of the thrashing machine and have holes in them. Any grain remaining in the straw is shaken off and falls onto the top sieve. This action allows the straw to float on the walkers to the straw chopper as it is discharged out the back of the combine.
After the primary separation at the cylinder, the clean grain and chaff fall through the concave and to the shoe, which contains the sieves. There are usually two sieves, one above the other and both cycle or bounce up and down moving material on each sieve to the rear of the combine. The sieves are metal frames that have many rows of "fingers". The angle of the fingers is adjustable to control the clearance thus the size of material passing through. The top sieve is set with more clearance than the bottom sieve to allow a gradual cleaning action. A fan blows air up through the sieves to keep chaff moving out of the combine while the heaver grain falls through the sieves. The large and heavy unthreshed heads, because of the sieve settings, fall off the back of the sieve where they are returned to the cylinder for re-threshing. Therefore, setting the concave clearance, speed, fan speed, and sieve size are critical to ensure that the crop is threshed properly. After passing through both sieves, the grain is clean of debris and is augured to the clean grain bin or “hopper”. All the chaff is dumped out the back with the straw.