The pious wouldn’t only express their reverence for G-d by being humble, and standing in awe and love in His presence; they’d revere Him by the quality of the things they’d use to fulfill His mitzvahs as well. As such, they’d only use a well-made pair of tephillin in prayer and a striking etrog and lulav on Sukkot, they’d always have a lush Shabbat meal prepared, and the like. And while that’s expected of all of us in fact, the pious would be sure to go to greater lengths to do it.
Now, some might raise the point that there seems to be no reason in the world why G-d would demand that; and that only we mere “humans, who are seduced by such vanity” would need to have our favors curried with fine accoutrements, “not G-d “who doesn’t care for such things, … and (is) transcendent of them”. After all, they’d argue, wouldn’t “it be enough for Him that the mitzvah was done faithfully?” however simply.
But they’d be wrong, as G-d’s own Torah in fact lays a lot of stress on fulfilling mitzvahs attractively. As Ramchal words it, in fact “we’re obliged to honor G-d even though He doesn’t need to be, and even though our acts of honor aren’t of any great importance or consequence to Him” at bottom.
Indeed, that’s just what the prophet Malachi was referring to when he said, “If you were to offer blind (animals) for sacrifice (for example), would that not be wrong? And if you were to offer a lame or sick animal, would that not be wrong? Offer (something like) that now to your governor (i.e., to any high official, and what would you suspect?). Would he be pleased with you or show you favor?” (Malachi 1:8). Of course not, is the implication, so why would you do that to G-d? It would behoove us all to use the finest things in our worship of Him.
(The truth of the matter is that we actually need to worship G-d with beautiful things, given human nature. As we’re impressed by appearances and lend a lot of weight to them, so we’d come to assume that G-d was unworthy of our honor if we weren’t expected serve Him honorably.)
Ramchal offers this model from the Torah, “the processional for the offering of the season’s first fruits (Bikkurim) in the Holy Temple exemplified (the idea of) beautifying mitzvahs” (see Deuteronomy 26:1-11). We’re taught that “an ox would proceed (those making the offering) with horns overlaid with gold and with a crown of olive branches…” (Bikkurim 3:3), and that “the wealthy would bring their offerings in golden baskets” (Bikkurim 3:8). And so the pious have always followed that standard.