Perhaps a brief look at the scripture itself is worthwhile. Let's journey back to Mary and Martha's home when Jesus of Nazareth visited. I'm in Luke 10, you should go there, too. I'll make it easy.
Ponder on that passage for a moment--Martha was about her business. And it was a very important business, too. Semitic tradition required ultimate hospitality (there are all sorts of beautiful stories about Abraham one can find which illustrate this point) and Martha was fulfilling that duty. Jesus, as I see it, very lovingly acknowledged her and, also very lovingly, showed her that, at this one specific moment, there was a different good to choose. That second good was the part which "would not be taken away."
Ponder on that passage for a moment--Martha was about her business. And it was a very important business, too. Semitic tradition required ultimate hospitality (there are all sorts of beautiful stories about Abraham one can find which illustrate this point) and Martha was fulfilling that duty. Jesus, as I see it, very lovingly acknowledged her and, also very lovingly, showed her that, at this one specific moment, there was a different good to choose. That second good was the part which "would not be taken away."
Life is full of "good parts" which present us with choices. Maybe your experiences have been different, but mine have shown that those "good parts" are never "perfect parts" or "perfectly-clear parts." In fact, my experience has been that I'm often faced with choosing between two things that are messy (oh, how I love that word!). My job is to determine which part is the "good" or, perhaps, "better" one. Circumstance often influences the outcome of that choice.
What are those parts that will not be taken away? I believe they all come down to one principle--Charity. Charity is the "pure love of Christ." I see that as a three-fold love: the love we receive from Christ, the love we have for Christ, and the love we express that is like that of Christ. I believe my life's purpose is to carve and stretch my heart to be a large and ready receptacle for such love. This requires conscious actions on my part.
I also firmly believe that I am here to experientially learn what that good (or, better) part is. This means I will be faced with some tough, tough choices which will do more than test my obedience; they will allow me to determine what I stand for. There's a difference. We can talk nuances sometime if you're interested...
One of those nuances can be found in Mormons' view of the Judeo-Christian creation myth. We maintain that Eve made a conscious choice and that Adam, when faced with keeping all God's commandments, realized such was impossible--at least in the context within which he found himself. In order to follow the command to "multiply and replenish the earth," Adam had to choose to partake of the forbidden fruit. Who forbade such an act? The very God who issued the command for man and woman to cleave to one another. Adam and Eve determined for themselves which was the "good part." The Book of Mormon affirms "Adam fell that men might be, and men are that they might have joy." Messiness was introduced in the opening act.
All of us have been or will be presented with such heart-wrenching, faith-shaking choices in our lives. For some, it is the choice between acceptance of a loved one and strict adherence to deeply-held religious beliefs. For others, it is the choice between acceptance of self and full participation in their larger community. In all of these choices, sacrifice is an integral part. We have the privilege and challenge of determining which sacrifices to make. We get to choose the "good part" which will not be taken away.
We get to work with God in forming our souls for eternity...