Sforno on Deuteronomy 16:21/ספורנו על דברים ט״ז:כ״א

1לא תטע לך אשרה, in this verse the Torah lists three items whose common denominator is that they appeal to the senses, are desirable, but at the same time are all spiritually negative, harmful. The first one is האשרה, something beautiful and decorative for buildings, but at the same time something ugly from the vantage point of holiness as it is usually a conduit leading to idolatrous practices. Seeing that this is so, we are commanded whenever faced with such choices to give preference to that which leads to spiritual righteousness at the expense of physical perfection or beauty. By the same token, we are to prefer spiritual qualities possessed by someone chosen as a judge to external features, impressive though they may be. The second item is המצבה, even though such a kind of altar was welcomed by G’d as an outlet for someone who wanted to bring an offering to G’d, this was before the Torah had been given. Consider, for example, Exodus 24,4 where the Torah welcomed 12 such monuments erected by Moses, where these monuments symbolised the fact that the person offering a sacrifice considered himself as constantly in the presence of the divine. (compare Psalms 16,8 שויתי ה' לנגדי תמיד, “I feel myself constantly in the presence of the Lord.”) The Jewish people had not been able to maintain this spiritual level after they had committed the sin of the golden calf. Even when such a מצבה is dedicated to heaven it had become hateful in the eyes of the Lord, i.e. G’d had expressed His distaste in Exodus 33,3, after having provisionally “forgiven” the people by appointing an angel to lead them to the Holy Land, but refusing to lead their ascent by His presence being among them. We encounter a similar concept described as the difference between an old man whose beard proclaims his respectability, as opposed to the old man whose beard is disheveled, i.e. reveals traces of a youth which was spent irresponsibly. We look for people whose exterior testifies to their blameless interior, character. [This metaphor is used by the Chazzan in his private introductory prayer on Yom Hakippurim. Ed.] The third item, also reminding us of the rejection of an externally basically beautiful animal as a sacrifice, is a series of blemishes, some quite minor, not affecting the value of the animal in question in the market place at all. Such a blemish in an animal worth 1000 dollars disqualifies it as an offering, whereas another similar animal worth one single dollar, but without such a blemish, is given preference over the far more expensive animal, which is rejected. The Torah gives us three examples to teach us basically the same lesson. What is true of the blemished animal for presentation on the altar, is equally true for the venerable old scholar who is afflicted with some character fault. We are to look further in order to find a less impressive individual not afflicted with such character fault.