I will follow you

"I will join you as a disciple" or "I am ready to follow you"

first let me say goodbye to those in my home

"before I do that, let me tell my people at my home that I am leaving"

Jesus responds with a proverb to teach the man about being his disciple. Jesus means that a person is not suitable for the kingdom to God if he focuses on people in his past instead of following Jesus. (See: rc://en/ta/man/translate/writing-proverbs and rc://en/ta/man/translate/figs-explicit)

Here "puts his hand to" something is an idiom that means the person starts to do something. AT: "No one who starts to plow his field" (See: rc://en/ta/man/translate/figs-idiom and rc://en/ta/man/translate/translate-unknown)

Anyone who is looking back while plowing cannot guide the plow where it needs to go. That person must focus on looking forward in order to plow well.

"useful for the kingdom of God" or "suitable for the kingdom of God"