Luke 10:38-42
David Horvath explains the basic lesson of discipleship taught by Jesus in this and other passages. Martha didn't miss out on salvation because she was busy serving the physical needs of Jesus and the disciples. Jesus pointed out to her that her worries and frustration over physical things should be secondary to learning about the spiritual mind of Christ.
Discipleship is the only way to Christian maturity. It doesn't happen as a matter of course, but must be chosen and deliberately and actively sought.