No one who puts a hand to the plow and looks back is fit for the kingdom of God.” Luke 9:62
This line was preceded by Jesus asking people to follow Him. They came up with one excuse after another to procrastinate. I'll bury my dad first, or say good bye to my friends and family. Jesus wanted their full and immediate commitment. For Jesus, asking them to follow Him was like helping Lot and his wife flee from Sodom and Gomorrah and telling them not to look back. But those fellows didn't see that.
God told Lot not to look back to watch his hometown being destroyed because it was thoroughly infected by rapists who stupidly tried to take the Angel of The Lord, but Lot's wife was curious to see the conflagration and turned into a pillar of salt.
Our journey to the kingdom of God is not a physical one like Lot's or even like the would-be followers would have been. So, let's just forget about this Mark and believe that it has nothing to do with us.
Except that these two stories repeat the very broad and familiar requirements to obey God without question (because we don't know all His reasons) and to be fully committed to the narrow path Christ ushers us onto in our spiritual journey to the kingdom of God, a.k.a. the Land of Immortality.
Looking back at our old life while aspiring to immortality is like trying to walk simultaneously on the highway and the narrow path.
This Mark reminds us to choose one or the other; it also reminds us that God didn't give us eyes on the back of our heads for a very good reason. Perhaps racehorses aren't the only ones who should be fitted with blinders.