The Midrash in Bamidbar Rabbah (chpt. 18) indicates that Shmuel HaNavi was equivalent to Moshe and Aaron, a concept supported by the verse in Tehilim: "מֹ֘שֶׁ֤ה וְאַהֲרֹ֨ן ׀ בְּֽכֹהֲנָ֗יו וּ֭שְׁמוּאֵל בְּקֹרְאֵ֣י שְׁמ֑וֹ Moses and Aaron were among His priests, and Samuel among those who called His name" (99:6). This raises the question of how Shmuel shares traits with both Moshe and Aaron.
Sefer Shem Mishmuel suggests that Shmuel’s status as a Nazir provides a partial answer, drawing a parallel to the birth of Shimshon HaGibor in this week’s Haftarah. HKB”H instructed Shimshon’s parents to ensure the child abstained from wine and strong drink, as it says "כִּֽי־נְזִ֧יר אֱלֹהִ֛ים יִֽהְיֶ֥ה הַנַּ֖עַר מִן־הַבָּ֑טֶן for the lad will be a nazirite to God from the womb" (Shoftim 13:5). The prohibition against alcohol for a Nazir is connected to the idea of concealment. When Shimshon’s father, Manoach, asked for the angel's name, the response was, "“וַיֹּ֤אמֶר לוֹ֙ מַלְאַ֣ךְ יְהֹוָ֔ה לָ֥מָּה זֶּ֖ה תִּשְׁאַ֣ל לִשְׁמִ֑י וְהוּא־פֶֽלִאי The angel of the Lord said to him: Why do you ask my name? It is Unknowable” (Shoftim 13:18). This implies that a Nazir’s role is characterized by privacy and hiddenness, whereas wine is known to reveal secrets—as it is said, "נכנס יין יצא סוד the wine enters, the secret is revealed".
In this regard, a Cohen shares similarities with a Nazir. Just as a Nazir operates in privacy, a Cohen brings the Ketoret, which halachically must be offered in silence and isolation. Furthermore, Cohanim have specific restrictions and a requirement for distinct vestments, symbolizing the covering of what is meant to stay hidden. This is reflected in the descriptions of Shmuel’s attire: "וּמְעִ֤יל קָטֹן֙ תַּעֲשֶׂה־לּ֣וֹ אִמּ֔וֹ His mother would make him a small robe (I Shmuel 2:19), אִ֤ישׁ זָקֵן֙ עֹלֶ֔ה וְה֥וּא עֹטֶ֖ה מְעִ֑יל An old man is ascending; and he is clad in a robe (I Shmuel 28:14)".
Conversely, Shmuel is likened to Moshe through their shared identity as Leviim. The service of the Leviim, such as singing in the Bais Hamikdash, represents an external form of devotion. Shmuel HaNavi integrated the qualities of both Aaron and Moshe; he possessed the deep internal focus of a Cohen (represented by Aaron) while also being qualified for the external spiritual duties of a Levi (represented by Moshe).