The Rebbe's guidance on relationships with relatives — parents and married children, in-laws, siblings — and on family harmony:
Peace in the family. Peace within the family is a vessel for blessing, material and spiritual (IK 1796), and even the worst peace is better than the smallest dispute (IK 2713). True family harmony often comes through humility (IK 6621). No matter how painful a family conflict, there is no room for despair; teshuvah and goodwill can heal it (IK 9633, 3799). Resolving family disputes often begins with spiritual steps such as family purity, together with practical ones (IK 3071). Avoid unnecessary conflict with family over religious practice (IK 10180), though peace at home must never come at the expense of Torah (IK 5841).
Parents and married children. Parents should help restore shalom bayis between a son or daughter and their spouse (IK 1233b, 3799). Shalom bayis problems are often rooted in spiritual matters rather than in the mother-in-law (IK 2938). On improving relations with one's parents, including avoiding disputes and seeking forgiveness, see IK 6670. Children's conduct is the source of their parents' joy (IK 3549).
Indirect influence. Indirect approaches — especially through friends — are often best for resolving family tensions and for influencing relatives toward Torah and mitzvos (IK 6861, 8601). Kindness toward relatives is a great mitzvah (IK 908).
Family and names. Naming a child is primarily the parents' decision, with sensitivity to grandparents (IK 2433, 2144). On a groom sharing his father-in-law's name, or a bride her mother-in-law's, see IK 2485, 6104, 10491. Both families should share in wedding costs (IK 2721). On siblings marrying into the same family, see IK 2276; on siblings living near and supporting their mother, see IK 10493.
See also: Marriage – Shalom bayis; Parenting – Honoring parents; Shidduchim – The parents' role.