The account of the anonymous woman who broke an alabaster flask and poured nard onto Jesus’ head (Mark 14) is difficult to relate directly to post-resurrection discipleship. I’ve never seen alabaster, and wouldn’t know nard if it hit me in the face, and, besides, even if I had and would, Jesus isn’t here.
We know that her act was criticized by others, even those close to Jesus, but Jesus commended her for it. Which shows that those close to Jesus don’t always ‘get it’ and sometimes place a good thing (caring for the poor) above the best thing (lavishing praise on the Christ who would soon be gone). It also shows that zealous acts of faith and worship are often a threat to moderate religion, which thrives on mediocrity and standard works-based feel-good-ism.
Perhaps a key to understanding this is to understand joy. God calls us to it, but we frequently find ourselves not knowing Him well enough to find our greatest joy in Him. Those who do — like the nard lady and naked-dancing David — pose a real threat to those of us who find joy in other things. Nard lady found joy in expending a very valuable item in worship; David in dancing naked before God. When we find our joy in such comparatively pedestrian things as sports results, market gains, and even children — all things that benefit us — that someone else expresses ultimate joy in (simply) God demonstrates in stark contrast our utilitarian happiness.
Nard lady sacrificed material wealth in worship of One who would suffer as substitute. She perhaps grasped the notion that the gospel, the good news, is about suffering: that either we endure it alone or Christ endures it alone. This is why what she did, but not her name, is proclaimed with the gospel — it embraced the suffering of Christ in her behalf.