וּבְנֵ֣י הַנֵּכָ֗ר הַנִּלְוִ֤ים עַל־יְהוָה֙ לְשָׁ֣רְת֔וֹ וּֽלְאַהֲבָה֙ אֶת־שֵׁ֣ם יְהוָ֔ה לִהְי֥וֹת ל֖וֹ לַעֲבָדִ֑ים כָּל־שֹׁמֵ֤ר שַׁבָּת֙ מֵֽחַלְּל֔וֹ וּמַחֲזִיקִ֖ים בִּבְרִיתִֽי׃
און די פֿרעמדגעבאָרענע װאָס באַהעפֿטן זיך צו גאָט, אים צו טאָן דינסט, און ליב צו האָבן דעם נאָמען פֿון גאָט, אים צו זײַן פֿאַר קנעכט; איטלעכער װאָס היט שבת אים ניט צו פֿאַרשװעכן,
Ibn Ezra
Also the sons of the stranger, etc. The eunuchs are mentioned before the sons of the strangers, because they are the last named (ver. 3). Comp. And I gave to Isaac, Jacob, and Esau, and I gave to Esau, etc. (Jos. 24:4).
Ibn Ezra
To serve him. The service of the Lord consists in keeping His commandments.
Tze'enah Ure'enah
“As for the foreigners who attach themselves to the Lord, etc.” [56:6]. The foreigners who cleave to God, serve Him and properly observe the Sabbath, I will bring them to My holy mountain, will rejoice with them in My house of prayer. I will accept their sacrifices, for My house shall be a house of prayer for all nations.