Or HaChaim on Leviticus 19:32/אור החיים על ויקרא י״ט:ל״ב

1 מפני שיבה תקום, "You shall rise in the presence of an aged person, etc." Kidushin 32 explains that the word שיבה refers to someone advanced in years, whereas the word זקן refers to someone who has acquired wisdom. The word תקום means to rise as a sign of respect, והדרת פני. The wording in the Talmud is difficult as in order to correspond to what the Talmud says the Torah should have written: מפני שיבה ומפני זקן תקום והדרת. Perhaps the Talmud intended to distinguish between different signs of recognition to be accorded to physical maturity, old age, and to spiritual maturity, i.e. זקנה. In the former case it suffices to rise from one's seat momentarily, whereas in the latter case one is to remain standing for longer; the idea is that זקנה, spiritual maturity, rates a greater degree of recognition than שיבה, mere physical old age.

2We may also take our cue from Bereshit Rabbah 65,9 where we are told that Abraham asked to look old in order that he could be told apart from his son Isaac who resembled him greatly (based on Genesis 24,1 ואברהם זקן). When the Torah says to rise on account of a man aged in years, this is the way to be מהדר, to lend distinction to someone like Abraham who was advanced in years.

3There may also be an allusion here to the statement in Bereshit Rabbah 12,6 that one of the consequences of Adam's sin was that he lost in "height," i.e. that the wicked do not attain their full height or that they shrink in height. G'd therefore commanded Adam to be sure to repent his error and to mend his ways so that he could attain his full stature. Our sages said in Yevamot 50 that if one possesses the necessary merit one is granted the full number of years allocated to him (70 or more) at birth; if one has not lived in accordance with G'd's commandments one forfeits some of these years and dies before one has completed the normal lifespan of 70 years. The word קומה therefore does not represent physical height but spiritual height. The measure of the verse then is: "if you want to reach a good old age, attain the spiritual height you are meant to attain!" The verse challenges each individual to develop to his full spiritual potential as much as it directs us to display honour for people who have attained old age. Inasmuch as Kohelet 12,1 has already told us that old age is frequently accompanied by afflictions so that one curses those years, the Torah suggests that the way to head off these frequent by-products of aging is to תקום, rise to one's spiritual stature מפני, on account of what might otherwise befall one in old age. Once one reaches that stage, one becomes totally dependent on G'd's personal and beneficial providence.

4The words והדרת פני זקן may even allude to one's own old age; our sages (Sukkah 53) are on record as saying about themselves: "hail to our youth which has not shamed our old age;" they referred to the kind of old age in which one can recall that one had led an exemplary life already from one's youth so that no one could point to a "skeleton in one's cupboard." The Torah therefore advises young men to lead the kind of lives now that would not make it necessary for them to ever be ashamed of their younger years. We are taught in Chagigah 14 that when a righteous person departs this life they compliment Abraham in heaven on the fact that this righteous person was a descendant of his. On the other hand, when a wicked person dies not only does no one compliment Abraham, but he is pained by the failure of that person to have become a penitent before he died. When the Torah speaks of "enhance the face of the old man," the reference is to Abraham who feels chagrined that not all of his descendants are true to his example. The Torah continues to warn us of what is in store in the hereafter by writing ויראת מאלוקיך, "and you shall fear your G'd." This refers to the fear of the punishment to be meted out when the soul comes up for judgment. אני השם, "I am the Lord." This refers to the reward for one's exemplary lifestyle, i.e. that one qualifies for life in the hereafter. Alternatively, these concluding words of our verse may illustrate both fear and love. G'd is telling us that He is to be both feared and loved. G'd's very name is the epitome of love, He is the root cause of all love.