Luke 9:62 - Ellicott's Commentary On The Whole Bible

No man, having put his hand to the plough... — The image which our Lord used was, as usual, one that went home to the personal experience of His hearers. They were of the peasant class, and they knew that the eye of the ploughman if he is to do his work well, must look straight before him at the line of the furrow which he is making. To look back, while working, is to mar the work entirely. The man who so looks is therefore, ipso facto, disqualified for the work of God’s kingdom.