Combining the principle that whatever is sown will also be reaped (Galatians 6:7-8) with the tendency towards increase means that no matter what a person sows—unless somebody or something intervenes and interrupts the cycle—more will be produced than was sown.
Living according to Christian standards, morals, and ethics can be faked for a while. Consider these verses: "Every good tree bears good fruit, but a bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit." Christian standards, morals, and ethics can be faked for a while, but no matter how guarded a person is, the fruits he produces will betray him. The principle Jesus teaches is also present in the Old Testament, written by Moses in Numbers 32:23, "Be sure your sin will find you out."
Bitterness, divisiveness, envy, jealousy, lethargy, and other faults of character will eventually show. One cannot accurately predict how much fruit will be produced because too many variables are involved. However, because of the principle of increase over what was originally sown—whether good or evil—there is every likelihood that more will be produced than was sown.