I believe that we can provide clarification based on a teaching in the Talmud Yerushalmi (R.H. 1, 3): "בנוהג שבעולם מלך בשר ודם גוזר גזירה, רצה מקיימה אינו רוצה אחרים מקיימים אותה, אבל הקב"ה אינו כן, אלא גוזר גזירה ומקיימה תחלה, מאי טעמא ושמרו את משמרתי אני ה', אני הוא ששימרתי מצוותיה של תורה תחילה". אמר רבי סימון כתיב מפני שיבה תקום והדרת פני זקן ויראת מאלקיך אני ה', אני הוא שקיימתי עמידת זקן תחילה". HKB”H Himself, so to speak, observes all the mitzvos of the Torah. This is in stark contrast to human kings; they are capricious; they may or may not comply with their own edicts, although their subjects are required to do so. Not so HKB”H; He observes His own edicts before requiring others to do so. What is the reason? Because it states (Vayikra 22, 9): “They shall guard My safekeeping . . . I am Hashem”—I am He Who keeps the mitzvos of the Torah first. Rabbi Simon said, it is written (ibid. 19, 32): “You shall rise in the presence of an old person, and you shall honor the presence of an elder, and you shall have fear of your G-d—I am Hashem.” I am the One Who first fulfilled standing in the presence of an elder. In other words, as an example, the Yerushalmi states that HKB”H was the first to observe the mitzvah of "מפני שיבה תקום והדרת פני זקן"--rising in the presence of an elderly person and honoring an elderly person.
The Pnei Moshe, explains that HKB”H did this when he rose, so to speak, for the sake of Avraham, who was elderly when he performed the mitzvah of “Bris milah.” As it is written (Bereishis 18, 1): "וירא אליו ה' באלוני ממרא והוא יושב פתח האהל כחום היום"—Hashem appeared to him (Avraham) in the plains of Mamre while he was sitting at the entrance of the tent in the heat of the day. Rashi comments based on the Midrash (B.R. 48, 7): Avraham wanted to stand (out of respect for the Divine Presence), but HKB”H said to him: “Sit, and I will stand; and you are a foretoken (sign) for your children; for I am destined to stand in the assembly of judges, while they are sitting”; as it says (Tehillim 82, 1): “G-d stands in the Divine assembly.”
Based on this teaching in the Yerushalmi, the Bnei Yissaschar (Sivan 2, 4) explains the formula established by Chazal for Berachos recited before performing mitzvos: "אשר קדשנו במצוותיו וצונו"—Who sanctified us with His mitzvos and commanded us. This implies that HKB”H sanctifies us "במצוותיו"—with the mitzvos that He Himself fulfills. Here is an excerpt from the Bnei Yissaschar: "והנה כביכול השי"ת בעצמו שומר תורתו ומקיים מצוותיו, כמו שאנו מברכין על המצוות אשר קדשנו במצוותיו - מצוותיו דייקא, כביכול אשר הוא בעצמו מקיימם, וכענין שמצינו בדברי חז"ל מנין שהקב"ה מניח תפילין, מנין שהקב"ה מתפלל". The Almighty Himself, so to speak, observes His Torah and fulfills His mitzvos, as indicated by the berachah recited over the performance of the mitzvos—"אשר קדשנו במצוותיו וצונו"—“Who sanctified us with His mitzvos and commanded us.” The formula specifies that they are His mitzvos—that He Himself, so to speak, fulfills. This coincides with the statement of Chazal (Berachos 6a): “How do we know that HKB”H puts on tefillin?” “How do we know that HKB”H prays?”
