When I first read the passage of Luke 19:38-42: " Now it came to pass, as they went, that he entered into a certain village: and a certain woman named Martha received him into her house. And she had a sister called Mary, which also sat at Jesus’ feet, and heard his word. But Martha was cumbered about much serving, and came to him, and said, Lord, dost thou not care that my sister hath left me to serve alone? bid her therefore that she help me. And Jesus answered and said unto her, Martha, Martha, thou art careful and troubled about many things: but one thing is needful: and Mary hath chosen that good part, which shall not be taken away from her," my sympathies were with Martha, as her request to me, seems quite reasonable, and I actually expected Jesus to gently rebuke Mary for not helping Martha, in which, perhaps later, they could both sit at the feet of Jesus.
Additionally, this passage of Luke contains an important clue which is Mary sitting at the feet of Jesus, in which previously in the reading of Luke 7:36-50, we are told the story of a sinful woman who brought in an alabaster jar of perfume, wetted Jesus' feet with her tears, then proceeded to wipe Jesus' feet with her hair, then kissed his feet and poured perfume on them, in which Jesus proceeds to then tell a parable and to forgive this woman of her sins. We are not told in Luke 7, of the woman's name, but in a later passage in John 11:2, we read: "It was that Mary which anointed the Lord with ointment, and wiped his feet with her hair, whose brother Lazarus was sick." Knowing this vital information, we now know that Mary was that sinner, forgiven by Jesus, who had wetted Jesus feet with her tears and later poured perfume on them, in which Jesus went to visit their home with her sister, Martha, and her brother, Lazarus, in whom He would later raise from the dead.
Now we have a better perspective because the story is more complete, Mary is at Jesus' feet, this time at their home, because she recognizes him as the Master, who previously forgave her of her sins. Her devotion of love of the Christ is sincere, focused, attentive, and dedicated. For Mary, it isn't so much that she doesn't realize that her sister Martha may need her assistance in the kitchen, it is instead the realization that Christ is that needful thing, that well in which the clear deep waters of forgiveness and love will never run dry and she wishes to drink deeply from it.
As for Martha, it isn't so much that she doesn't recognize the Master with her eyes, but instead that she doesn't recognize the Master with her heart. Martha is concerned about this material world, taking care of her friends and neighbors through the usual niceties that are appropriate in their place, but she fails to recognize that through all her troubles and cares she is in the presence of the One true path that is the true calling of our life. The message for Martha is quite clear, that while we do need to be attentive to the letter of the law, it is far more important to be attentive to the Spirit of the law. That for all of our running around, of all our responsibilities of home and hearth, that there is a meaning behind our existence and that meaning is our need for salvation, to find God, to be with Christ, to do the right thing. We will never hear that still small voice within, if we do not shake loose from the shackles and blinders of a life both spent unexamined and a life also spent without examining or seeking for its eternal rewards.