stacking firewood and picking up pins

To pick up a pin for love can convert a soul.

St Therese of Lisieux said that and I keep thinking about it when I'm doing something around the house.  (Today, I was stacking firewood in preparation for a possible snowstorm tomorrow).

How do ordinary, small actions that people do every day become invested with eternal significance?

The Catholic Encyclopedia describes the meaning of the word sacrament:

Taking the word "sacrament" in its broadest sense, as the sign of something sacred and hidden (the Greek word is "mystery"), we can say that the whole world is a vast sacramental system, in that material things are unto men the signs of things spiritual and sacred, even of the Divinity. "The heavens show forth the glory of God, and the firmament declareth the work of his hands" (Psalm 18:2). The invisible things of him [i.e. God], from the creation of the world, are clearly seen, being understood by the things that are made; his eternal power also, and divinity" (Romans 1:20).

This seems to relate to what St Therese said -- because picking up a pin is nothing in itself, that is plain to see, but it becomes something by being done with love.   I know that for St Therese, "love" was the inclination of a little, helpless soul towards its Maker.

I saw something further; that Our Lord's love shines out just as much through a little soul who yields completely to His Grace as it does through the greatest. ... He has, in fact created the child who knows nothing and can only make feeble cries; and the poor savage with only the natural law to guide him; and it is to hearts such as these that He stoops. 

There is no alchemy in the material world, but there seems to be one in the sacramental order, where simple things -- water, wine, bread, oil -- become vested with significance even beyond their natural and analogical qualities.  Not in the same way, but nevertheless by the same Grace, little humble actions, valueless in themselves, have the potential to ring like gold -- like the widow's mite.  Perhaps, even, the smaller the action or capability, the more God can do.

My grace is sufficient for thee: for my strength is made perfect in weakness.

I wish I knew better how that takes place -- but words like "sacramentum" and "mystery" tell me I don't have to understand completely in order to participate.   Grace is a participation in the life of God, the Catechism says.   Participation means sharing in the action of something bigger.