The word “Kamma” here refers to the law of cause and effect or the law of reason and result of Buddhism and the word “Mangala” here refers to superstition as described above.
In the law of cause and effect, the Exalted one taught by comparing cause and effect to seeds of plants as follows: “yadisam vappate bijam tādisam labhate phalam kalyanakārī kalyanam papakārī ca papakam. One sow what species of seeds always reaps such species of crops, one who habitually does good always gains good results, one who routinely does bad always gains bad results.”
The Lord Buddha taught this teaching, his goal is to make beings believe what the Law of Kamma is, which always produces results in accordance with what has been done by beings. Seed of rice such as glutinous rice and the like that is sown into paddy rice field, whenever its fruition season is complete, always produces result as glutinous rice is the same as its seed, likewise, good action is seed that beings have sown -have already done, whenever the time it produces result is enough, always produces good result as its seed, bad action is seed that beings have sown, whenever the time it produces result is enough, always produces bad result as its seed. To teach by comparing the nature of Kamma to the nature of plant seed is to enlighten Buddhists through comparison to what observably exists in the world. When Buddhists have realized what really exists, Buddhists will believe without doubt.
The purpose of Buddhism in the propagation of belief is to take cause and effect to enlighten people, not to tell them to keep believing, to keep following without considering finding cause and effect yet.
To be the adherents of Buddhism, we must be the one who is serious in rationality. Before believing in something, we must consider reason and result for what really is and then believe in it, not merely keep believing blindly.
Belief in cause and effect or belief in reason and result is the virtue of good Buddhists, the contrary fact, superstitious belief is the flaw of Buddhists. To become good Buddhists, we must believe in the cause and the result of the cause because believing in the cause and the result of the cause is the act of showing real and right comprehension of Buddhists.