In a situation where most global statistics show a decrease in marriages, an increase in illegitimate children, and divorce, the danger of weakening the foundation of the family and its collapse is considered one of the cultural problems at the global level. A complete solution to this problem requires interdisciplinary research in the fields of sociology, psychology, ethics, jurisprudence, law, etc., in the form of a comprehensive research project. The religion of Islam has answers with different ethical, jurisprudential, etc. perspectives for strengthening the family. The verse of tranquility (Rum: 21), by explaining the ethical principles of strengthening the family, answers an important part of the ethical dimension of this issue. This research, with the aim of explaining the ethical principles of strengthening the family from the verse of tranquility and its examples from the behavior and words of the Infallibles, has analyzed the content of the verse using a library method and has concluded that the principle of mawaddah means intense love that manifests itself in behavior, and the principle of rahma means gentleness and compassion in the path of the other’s development. These two principles play an important role in ensuring the mutual rights of members as two basic pillars in the family. There are numerous examples of these two principles in the behavior and words of the Imams (Peace Be Upon Them). Among the examples of mawaddah in narrations, we can mention verbal expressions of love, couples working in the house, making marital relations enjoyable, avoiding angering one’s spouse, and providing financial support. Also, examples of rahma in narrations include compassionate reminders of wrongdoings, constant tolerance, gentle talk, and efforts to adapt.