Luke 10:38-42.
When Jesus was at Martha and Mary's house, Mary sat at Jesus' feet and was listening to him. Martha complained about having to be serving people alone with no help from Mary. Jesus said to Martha that there is only one thing that is needed, and Mary has chosen the good one. That won't be taken from her.
Maybe Jesus wanted Marta to listen to him as well, and that might have been the only necessary thing there.
