Resources for Chagigah daf 16
1. The גמרא says that a person should not look at the כהנים when they duchen as their eyes would be damaged since the שכינה is שורה between their fingers. See תוספות in ד"ה בכהנים who says that it should come out from our גמרא that one is allowed to look at the fingers of כהנים nowadays since there is no שכינה being שורה outside the מקדש. However, he brings a גמרא in מגילה that forbids a כהן בעל מום to duchen even nowadays because people may come to look at his hands. תוספות explains, based on a ירושלמי, that the reason one cannot look at a כהן בעל מום’s hands nowadays is not because he will become blind but rather because it will cause people to be מסיח דעת from the ברכת כהנים. See the דבר אברהם in חלק א סימן ל"ה אות בּ who proves from here that תוספות’s opinion (which is really just quoting the ירושלמי) must be that it is not just the כהנים who a have an obligation to duchen; rather even the ישראלים themselves have an obligation to be מתברך! If this were not true, why would we care if the ישראלים were מסיח דעת? It must be that they have a מצוה as well. According to this, if a Jew already received ברכת כהנים that morning and was hearing it a second time, he would be allowed to stare at the כהנים’s hands since it isn’t his מצוה anymore. The ספר חרידים in חלק העשין בפּה פּרק ד' עשה י"ח also famously holds that there is a מצוה on the ישראל himself to be מתברך. However, see the ריטב"א in סוכה דף ל"א: ד"ה אמר מר who says that there is no מצוה on the ישראל at all. See the מגן אברהם in סימן קכ"ח ס"ק ל"ה who says that the way a person’s eyes would be damaged even in the time of the בית המקדש was only if they stared intently at the כהן’s fingers, but just a quick look would not hurt. Nonetheless, it is a lack of כבוד השכינה to even look for a second. Nowadays, the reason we don’t look at the כהנים’s hands is just a זכר למקדש.
2. The גמרא quotes the מחלוקת about סמיכה and then quotes רב יוחנן as saying that we should not take שבות lightly as great people argued over סמיכה. See the גמרא in ביצה דף כ that brings two possibilities as to what the מחלוקת was about. One possibility is that they disagreed as to whether there was is a חיוב סמיכה by a קרבן חובה at all. The second possibility is that they argued if we hold תיכף לסמיכה שחיטה or not. The question is that both of these possibilities are a מחלוקת regarding a דין דאורייתא, so how could רב יוחנן learn from here the power of a שבות? See תוספות there in ד"ה דלא גמרי who seems to say that רב יוחנן is actually a third opinion and he disagrees with the תנאים in מסכת ביצה and holds the תנאים in our משנה argued about the שבות of being משתמש בבעל חי. See the שפת אמת here who thinks that רב יוחנן must found some other ברייתא that says the מחלוקת in our משנה is about שבות.
See also the טורי אבן here who asks why we don’t apply the principle of אין שבות במקדש and allow סמיכה according to all? He answers that this principle only applies where the מצוה must be done in the בית המקדש, as opposed to here where סמיכה can be done outside the עזרה.
3. The גמרא says that women do not need to do סמיכה. There is a fundamental question here: we know the purpose of סמיכה is to declare that you are sending the animal off as a sacrifice to be killed instead of you and that it should be an atonement for you. If so, how could someone who is obligated to bring a קרבן ever skip that step? Isn’t that the whole point? See Rav Hirsch in the beginning of ויקרא in פּסוק ה who asks this question and says that all of the people who are exempt from סמיכה have something in common—they are all not people who we would typically send as representatives of כלל ישראל. Rav Hirsch suggests that סמיכה means you are standing up as a representative of כלל ישראל against yourself and indicating that what is about to take place is being done in your name and in the name of כלל ישראל. This is why there is no סמיכה by a במה since by a private מזבח you are not representing כלל ישראל.
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