Ethics: code of behaviour, system of moral principles/values based on beliefs about what is right and wrong
Morals: relating to the distinction between good and bad or right and wrong
Srila Prabhupada views morality, religiosity, and piety as more or less synonymous (Srimad-Bhagavatam 1.16.18p, Srimad-Bhagavatam 1.16.20 purport, Srimad-Bhagavatam 4.21.31 purport) But he does make a distinction: moral instructions with God in the centre are religious principles, otherwise they are sub-religious principles. (Srimad-Bhagavatam 2.7.37 purport)
The following examples are moral and ethical injunctions/principles taken from Srila Prabhupada's books. Doubtlessly, many more could be added to this list.
Now all of these principles may seem straightforward, but morality and ethics can be a complex subject matter.
Now read the following story
In the Mahabharata, Lord Krishna, the Supreme Personality of Godhead, tells a story to the Pandavas about the meaning of truth. This story continues to be told by great thinkers all over the world, often, and they do not even know that Sri Krishna told it in the Mahabharata. It is usually offered as a test case against the absolutist version of truthfulness in the world.
Lord Krishna's friend Arjuna had vowed to kill anyone who suggested that he should give away his Gandiva bow. In a moment of anger when Yudhisthira was disappointed that Arjuna could not kill Karna, Yudhisthira suggested that Arjuna could give the Gandiva bow to someone more qualified. When Arjuna drew his sword against Yudhisthira, Lord Krishna intervened and told His story.
Once there was an ascetic named Kosikatha who lived a small distance from a village. He had made a vow, "I will only speak the truth," and had become famous as the one who never told a lie. One day, innocent persons seeking refuge from robbers entered the forest near the dwelling of the ascetic. The robbers soon arrived searching for the men. They approached Kosikatha and inquired, "By which path have these men gone?" Kosikatha replied, "They have entered the forest just near here." The robbers then found and slaughtered the innocent persons and took their wealth. For this sin, Kosikatha fell into hellish life and suffered greatly.
Lord Krishna then drew the moral from His story. He said, "There must be some indication of distinguishing virtue from sin. Therefore great sages have indicated that seeing through the eyes of scriptures does not provide for every case. Hearing this from Me you should now decide whether your brother should be slain." In this story and other explanations, Lord Krishna found a way to preserve Arjuna's vow, while at the same time avoiding the killing of Yudhisthira.
The situation: Asvatthama was the son of Dronacarya, a brahmana and Arjuna's teacher. Towards the end of the Battle of Kuruksetra, Asvatthama killed Draupadi's five sons while they were sleeping. Arjuna promised Draupadi that he would capture Asvatthama and punish him by death. After Arjuna had captured him, he brought him back to the camp where the Pandavas and Draupadi were staying.
What are the arguments for and against killing Asvatthama?
For solution see Srimad Bhagavatam 1.7.55–7