1 Timothy 5:4
But if any widow have children or nephews, let them learn first to shew piety at home, and to requite their parents: for that is good and acceptable before God.
Note 12 at 1Ti 5:4: The English word "nephews" is a little misleading. The Greek word used here, "EKGONOS," means "a descendant, i.e. (specially) grandchild" (Strong's Concordance). Therefore, Paul was admonishing children or grandchildren to take care of the widows in their families.
The New International Version translates this verse as "But if a widow has children or grandchildren, these should learn first of all to put their religion into practice by caring for their own family and so repaying their parents and grandparents, for this is pleasing to God."
Note 13 at 1Ti 5:4: Paul said that widows for whom the church is to be responsible are those who have no family to help them. If widows have children or grandchildren ("nephews" - see note 12 at this verse), then those relatives are to take the responsibility of financially supporting them. Paul was establishing a principle even for our times. Family members are to take care of their own.
Paul expounded on this in 1Ti 5:8 (see notes 20-22 at that verse).
Note 14 at 1Ti 5:4: The word "requite" means "to make repayment or return for" (American Heritage Dictionary). This implies that children and grandchildren have a debt to their parents that should be paid in a time of need (see note 8 at 1Ti 5:3). This is speaking specifically of financial assistance but would certainly extend to other forms of kindness and love.
Jesus made this same point in Mr 7:9-12 when He spoke of people taking care of their parents. Jesus even dealt with this issue while hanging on the cross when He told His apostle John to take care of His mother (Joh 19:25-27). One of the Ten Commandments is to honor one's father and mother (Ex 20:12). This is a well-established command in Scripture. Charity has to begin at home.