peace and prosperity in the household in Kanji

It means that the family will be safe and free from various calamities in that year, and that the family will be prosperous and all family members will be healthy and have a stable spirit and full of vitality.
Japanese says “Ka Nai An Zen”.

Examples of English translations

peace and prosperity in the household.
safety of one’s (own’s) family.

The love for family is common to all mankind

“家内安全” is one of the words of the annual Shinto prayer for the safety and health of the whole family, but there are no restrictions on it.
The wish for family is common to all mankind and is an area that no one can violate. Therefore, anyone can use it.
The first two letters “家内” refer to “家屋” or “people in the house” and thus “家庭” or “family”. When “家内” is used to mean “a family,” it also includes “relatives. Since “家内” is also used to mean “wife,” be careful not to misuse the word to pray for your wife’s safety.