Luke 9:
See also Let the dead bury their own dead
Ellicott's Commentary for English Readers:61 Yet another said, “I will follow you, Lord, but let me first say farewell to those at my home.” 62 Jesus said to him, “No one who puts his hand to the plow and looks back is fit for the kingdom of God.”
This guy's heart is divided. He is not competent. Jesus demands the best of our efforts to work for him. We should work for Jesus with our whole hearts. I don't think Jesus was particularly against him saying goodbye to the people in his house. Jesus knew his heart was split between Jesus and his family.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.
See also Let the dead bury their own dead