In Genesis 37:12, the appearance of two dots over אֶת in לִרְע֛וֹת אֶׄתׄ־צֹ֥אן אֲבִיהֶ֖ם is curious. Unique to Hebrew, אֶת is a definite direct object marker, but does not have a translatable meaning. Why are there dots over a word that has no "meaning"?
(יב) וַיֵּלְכ֖וּ אֶחָ֑יו לִרְע֛וֹת אֶׄתׄ־צֹ֥אן אֲבִיהֶ֖ם בִּשְׁכֶֽם׃
(12) One time, when [Joseph's] brothers had gone to pasture their father’s flock at Shechem,
Interestingly, there is a similar verse in I Samuel without dots over אֶת in לִרְע֛וֹת אֶת־צֹ֥אן אָבִ֖יו.
(טו) וְדָוִ֛ד הֹלֵ֥ךְ וָשָׁ֖ב מֵעַ֣ל שָׁא֑וּל לִרְע֛וֹת אֶת־צֹ֥אן אָבִ֖יו בֵּ֥ית לָֽחֶם׃
(15) and David would go back and forth from attending on Saul to shepherd his father’s flock at Bethlehem.
Besides having the construction [*]לִרְע֛וֹת אֶת־צֹ֥אן אָבִ֖י, these two verses have other similarities. Both involve many brothers whose (next-)youngest brother later becomes the leader of Israel, Joseph and David, respectively. These young brothers are later sent by their fathers to check up on their older brothers. In both cases, the arrival of the young brother results in an angry reaction from at least one older brother (e.g., see Genesis 37:19 and I Samuel 17:28).
Why do Genesis 37:12 and I Samuel 17:15 differ regarding dots over אֶת in the same construction in similar narratives about brothers?
Several commentators (e.g., Rashi) state that the dots over אֶת in Genesis 37:12 indicate that Joseph's brothers were doing something inappropriate instead of (and/or while poorly) shepherding their father's flock of sheep.
לרעות את צאן. נָקוּד עַל אֶת, שֶׁלֹּא הָלְכוּ אֶלָּא לִרְעוֹת אֶת עַצְמָן:
לרעות את צאן TO FEED THE FLOCK — The word את has dots above it, to denote that they went only to feed themselves (Genesis Rabbah 84:13).
Particular words connected to the dots over אֶת help to clarify the interactions between Joseph and his brothers. It is helpful to look at Genesis 37:12 with its two subsequent verses. In these three verses (Genesis 37:12-14), two similarly spelled verbs (often homophones) are used: לִרְעוֹת (to pasture, shepherd, or tend) and לִרְאֹת (to see or look; e.g., see Genesis 11:5).
(יב) וַיֵּלְכ֖וּ אֶחָ֑יו לִרְע֛וֹת אֶׄתׄ־צֹ֥אן אֲבִיהֶ֖ם בִּשְׁכֶֽם׃ (יג) וַיֹּ֨אמֶר יִשְׂרָאֵ֜ל אֶל־יוֹסֵ֗ף הֲל֤וֹא אַחֶ֙יךָ֙ רֹעִ֣ים בִּשְׁכֶ֔ם לְכָ֖ה וְאֶשְׁלָחֲךָ֣ אֲלֵיהֶ֑ם וַיֹּ֥אמֶר ל֖וֹ הִנֵּֽנִי׃ (יד) וַיֹּ֣אמֶר ל֗וֹ לֶךְ־נָ֨א רְאֵ֜ה אֶת־שְׁל֤וֹם אַחֶ֙יךָ֙ וְאֶת־שְׁל֣וֹם הַצֹּ֔אן וַהֲשִׁבֵ֖נִי דָּבָ֑ר וַיִּשְׁלָחֵ֙הוּ֙ מֵעֵ֣מֶק חֶבְר֔וֹן וַיָּבֹ֖א שְׁכֶֽמָה׃
(12) One time, when his brothers had gone to pasture their father’s flock at Shechem, (13) Israel said to Joseph, “Your brothers are pasturing at Shechem. Come, I will send you to them.” He answered, “I am ready.” (14) And he said to him, “Go and see how your brothers are and how the flocks are faring, and bring me back word.” So he sent him from the valley of Hebron. When he reached Shechem,
Given the adjacency of these two similar verbs, the appearance of אֶׄתׄ immediately after לִרְע֛וֹת arguably suggests that the verb here should be (understood as) לִרְאֹת instead of לִרְעוֹת, with אֹת substituting for עוֹת in לִרְעוֹת. The purpose of the dots over אֶת then seems to be as an indicator of this substitution for interpreting the text, if not (also) as an indicator of uncertainty in the text here between לִרְאֹת and לִרְעוֹת.
This rendering is plausible in two ways. In the plain sense, it suggests that Joseph's brothers were not pasturing their father's flock. Beyond that, according to Genesis 37:10-11, Joseph's brothers were "wrought up at him" and likely sought an excuse (e.g., to see their father's flock of sheep in Shekhem) to get far away from him (see 13th-century commentator Chizkuni on Genesis 37:12).
(י) וַיְסַפֵּ֣ר אֶל־אָבִיו֮ וְאֶל־אֶחָיו֒ וַיִּגְעַר־בּ֣וֹ אָבִ֔יו וַיֹּ֣אמֶר ל֔וֹ מָ֛ה הַחֲל֥וֹם הַזֶּ֖ה אֲשֶׁ֣ר חָלָ֑מְתָּ הֲב֣וֹא נָב֗וֹא אֲנִי֙ וְאִמְּךָ֣ וְאַחֶ֔יךָ לְהִשְׁתַּחֲוֺ֥ת לְךָ֖ אָֽרְצָה׃ (יא) וַיְקַנְאוּ־ב֖וֹ אֶחָ֑יו וְאָבִ֖יו שָׁמַ֥ר אֶת־הַדָּבָֽר׃
(10) And when he told it to his father and brothers, his father berated him. “What,” he said to him, “is this dream you have dreamed? Are we to come, I and your mother and your brothers, and bow low to you to the ground?” (11) So his brothers were wrought up at him, and his father kept the matter in mind.
Use of לִרְאֹת instead of לִרְעוֹת makes sense also concerning Joseph's earlier interactions with his brothers in Genesis 37:2.
(ב) אֵ֣לֶּה ׀ תֹּלְד֣וֹת יַעֲקֹ֗ב יוֹסֵ֞ף בֶּן־שְׁבַֽע־עֶשְׂרֵ֤ה שָׁנָה֙ הָיָ֨ה רֹעֶ֤ה אֶת־אֶחָיו֙ בַּצֹּ֔אן וְה֣וּא נַ֗עַר אֶת־בְּנֵ֥י בִלְהָ֛ה וְאֶת־בְּנֵ֥י זִלְפָּ֖ה נְשֵׁ֣י אָבִ֑יו וַיָּבֵ֥א יוֹסֵ֛ף אֶת־דִּבָּתָ֥ם רָעָ֖ה אֶל־אֲבִיהֶֽם׃
(2) This, then, is the line of Jacob: At seventeen years of age, Joseph tended the flocks with his brothers, as a helper to the sons of his father’s wives Bilhah and Zilpah. And Joseph brought bad reports of them to their father.
The construction הָיָ֨ה רֹעֶ֤ה אֶת־אֶחָיו֙ בַּצֹּ֔אן is odd. One way to translate it is: [17-year-old Joseph] would shepherd his brothers among the sheep. Could this be some kind of allusion to his dreams about ruling over his brothers? The 16th-century Italian commentator Sforno indicates that "[Joseph] was giving guidance to them and instructed them in the finer points of being successful shepherds." (It is unclear whether Joseph's guidance is well-received by his (older) brothers, or is annoying to them, coming from a precocious younger brother. Sforno notes Joseph's relative inexperience (וְה֣וּא נַ֗עַר), being only 17.)
Given that the same verse (Genesis 37:2) later states that "Joseph brought bad reports of them to their father" (וַיָּבֵ֥א יוֹסֵ֛ף אֶת־דִּבָּתָ֥ם רָעָ֖ה אֶל־אֲבִיהֶֽם), perhaps the same construction should be understood, by way of the substitution, as if written הָיָ֨ה רֹאֶה אֶת־אֶחָיו֙ בַּצֹּ֔אן: [Joseph] would see his brothers among the sheep. With this understanding, Joseph would report (as an eyewitness) his brothers' inappropriate behavior while supposedly shepherding their father's flock of sheep. (Joseph's reporting would also motivate his brothers to come up with the excuse above to get away from him.)
Connected to Joseph's reporting, the construction דִּבָּתָ֥ם רָעָ֖ה is also odd. The first word (דִּבָּתָם) means "defamation of them", so why is רָעָה (bad) necessary after it? The same word (without a suffix) appears in Numbers 13:32 in "דִּבַּ֤ת הָאָ֙רֶץ֙" (defamation of The Land [of Israel]). Perhaps דִּבָּתָ֥ם רָעָה here should be read as דִּבָּתָ֥ם רֹעֶה to suggest that Joseph gives reports about his brothers' poor shepherding practices in particular (see Sforno's commentary on וַיָּבֵ֥א יוֹסֵ֛ף אֶת־דִּבָּתָ֥ם רָעָ֖ה).
These plausible interpretations of the text by substituting לִרְאֹת for לִרְעוֹת lend support to the idea that the purpose of the dots over אֶת in לִרְע֛וֹת אֶׄתׄ־צֹ֥אן אֲבִיהֶ֖ם is to indicate substituting אֹת for עוֹת in לִרְעוֹת for interpretation, if not also to indicate uncertainty in the text here between לִרְאֹת and לִרְעוֹת.