Luke 10:38-42 is the Gospel of the ancient Assumption Mass Gospel (1962 Missal) which ends "Mary has chosen the best part, and it will not be taken away from her," that also being the communion antiphon for that same Mass: Optimam partem elegit sibi Maria, quae non auferetur ab ea in aeternum.
This is a very legitimate analogical use of sacred scripture. One might legitimately ask: might not our Lord have also intended to mean the greatest Mary when he said that "Mary" has chosen the best part which would not be taken from her? In any case, God is the primary Author of scripture and he intends several levels of understanding in every text. Lazarus' and Martha's sister is here a type, a shadow, of The Most Blessed Virgin Mary, Assumpta.
A similar application is made in reference to Saint Joseph using the Exodus passage referring to the patriarch Ite ad Joseph. Joseph the Patriarch is a type of Saint Joseph of Nazareth.
Personally, I think this Gospel is a better choice for the Assumption Mass than the entirely too often repeated Annunciation Gospel because at least it alludes to Mary's eternal reward which is the meaning of this feast.