When the time comes when Jesus is no longer poor or hungry or thirsty or able to be tempted, then Mary alone–that is, spiritual activity–will occupy the whole of the house–that is, our soul. Saint Benedict saw this, or rather the Holy Spirit in Saint Benedict. That is why he did not say and decree that we be intent only on lectio, like Mary, and lay aside work, like Martha, but that he commended both to us, allotting certain times to Martha’s work and certain times to Mary’s work.
These two activities were perfectly present in the Blessed Mary, our Lady. The fact that she clothed our Lord, that she fed him, that she carried him and fled with him to Egypt–all this pertains to physical activity. But that she treasured all these words, pondering them in her heart, that she meditated on his divinity, contemplated his power and savored his wetness–all this pertains to Mary. Accordingly the Evangelist beautifully says: Mary, sitting at the feet of Jesus, listened to his word.
In the role of Martha, Blessed Mary did not sit at Jesus feet. Instead, I should think, the Lord Jesus himself sat at the feet of his dearest mother: for as the Evangelist says, he was subject to them, that is, to Mary and Joseph. But in that she saw and recognized his divinity, beyond doubt she sat at his feet. For she humbled herself before him and reckoned herself his handmaid. In the role of Martha, she tended him as someone weak and small, hungry and thirsty; she grieved at his sufferings. In the role of Mary, she entreated him as Lord, worshipped him as Lord and yearned with all her might for his spiritual sweetness.
Since, however, each of us must practice both these roles, we must surely do Martha’s task at certain times and, at certain times, Mary’s task.
From Aelred of Rievaulx’s Sermon 19 for the Assumption of Saint Mary, The Liturgical Sermons, CF 58, pp 170-71, 272