Literal translation of this proverb would be: "Pumpkin vines do not bear calabash."
Pumpkin vines and calabash trees are very different. The vine grows on the ground, while the tree is tall and straight. But their fruits look alike even though people can eat pumpkin but not calabash.
Haitians say this proverb to show that things don't surprise them like the deeds of wrong doer or the good results from cumulative good actions. They say that to show that we cannot expect good results from bad actions vice versa.
Let us be careful in our language, behavior, and thoughts because they drive our actions.
In Luke 6:45 the Bible tells us: “A good person produces good things from the treasury of a good heart, and an evil person produces evil treasures from the treasury of an evil heart. What you say flows from what is in your heart.”