A plow is a tool that is used to break up the soil so that plants can grow. The plow is made up of several components and each component needs to be carefully manipulated in order for the plow to work properly. If the plowman is not careful in his plowing, it will result in crooked furrows in the ground.
The meaning of the idiom "hand to the plow" (Luke 9:62) is to get up and keep going in the right direction, no matter how hard it may be. It is a reminder that we have to be willing to endure trials and persecution in order to serve God.
When Jesus is asked about the cost of following Him, He uses a metaphor from agriculture to help His disciples understand what He meant. Basically, He tells them that they can't divide their attention between spiritual goals and the things of this world.
It's not easy to follow Jesus, and it's even more difficult if you don't put your whole focus on the mission at hand. It's a challenge that we have to overcome, and it can be a lot of work.
There are a number of reasons why we have to put our hand to the plow and keep on moving forward in our journey toward Jesus. It's not always the most exciting thing in the world, but it is our only real chance at living a fulfilled life.
There are many temptations to give up on the idea of following Christ, but Jesus is clear that if we do so we will not be fit for His kingdom. The Bible records a number of instances in which people hesitate to follow Christ: They fall asleep when He asks them to pray, they bail out after His arrest, Peter denies Him three times, and Thomas doubts the resurrection.