sources mekorot - Adding stones or bricks to the Bais Hamikdash

As a child I was told, and now my children are being told, that when they do a Mitzva a brick gets added to the Bais Hamikdash. As pointed out by DoubleAA, the Rambam says that it is preferable to build the Bais Hamikdash with stones. As pointed out by Isaac Moses, here's an example of this concept presented by a teacher of children: "Rabbi Yitzchok Wolf, the dean of Cheder Lubavitch". Is there an earlier source that for each Mitzva either a stone or brick gets added to the building of the third temple?