Final answer:
The greatest commandment, according to Matthew 22:39 in the New Testament, is to love one's neighbor as oneself. This commandment is a key ethical principle in Christianity and is similar to teachings in Judaism and the Bahá'í faith, emphasizing love and compassion towards others.
Step-by-step explanation:
The greatest commandment according to the teachings of Jesus in the New Testament of the Bible is expressed in Matthew 22:39, where Jesus states, "Thou shalt love thy neighbor as thyself." This commandment emphasizes the importance of love and compassion towards others, irrespective of their background, appearance, or beliefs. It is seen as a foundational ethical principle not only in Christianity but also mirrored in various forms in other religious traditions, such as Judaism and the Bahá'í faith.In Judaism, for example, a similar sentiment can be found in Leviticus 19:18 and is also famously encapsulated in the teachings of Hillel in the Talmud, Shabbat 31a: "That which is hateful to you, do not do to your fellow. That is the whole Torah; the rest is the explanation; go and learn it." The Bahá'í command echoes this as well, advising individuals not to ascribe to others what they would not want for themselves and to avoid speaking falsely. In Christianity, the concept of the greatest commandment expands upon the Ten Commandments given to Moses, which include other moral directives such as prohibitions against idolatry, adultery, theft, and bearing false witness. However, Jesus' emphasis on love as the greatest commandment is a unifying theme that encapsulates the spirit of these individual mandates.