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, or 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, and morals, and ethics can be faked for a while. But, no matter how guarded a person is, the fruits produced will betray him. That principle that Jesus gave was also given in the Old Testament by Moses, in Numbers 32:23, where Moses said you can "be sure your sin will find you out."
Bitterness, divisiveness, envy, jealousy, lethargy will eventually show. How much of the fruit will be produced cannot be accurately predicted because there are too many variables involved. But because of the principle of increase over what was originally sown—whether good or evil—there is every likelihood that more is going to be produced than was sown.