Lois (desirable) and Eunice (good victory) were mother and daughter, and the grandmother and mother of Timothy. Both were a Jewess. Lois instructed both her daughter and grandson in learning the Old Testament. Timothy was brought up in the Jewish faith by both of these women and Paul gave both of them credit for Timothy's spiritual instruction.
(2 Timothy 1:5, 3:15, and Acts 16:1)
It's our responsibility to bring up our children in the "genuine faith", but our duty doesn't stop there. We are to continue teaching our grandchildren about Jesus!!!