Isaiah 44:15(MT)
וְהָיָה לְאָדָם לְבָעֵר, וַיִּקַּח מֵהֶם וַיָּחָם אַף-יַשִּׂיק וְאָפָה לָחֶם אַף-יִפְעַל-אֵל וַיִּשְׁתָּחוּ עָשָׂהוּ פֶסֶל וַיִּסְגָּד-לָמוֹ.
Let’s take a moment to examine the phrase in question and see what it actually reads. If I were reading this verse I would translate the phrase in question as “he that fashions a god and worships it, he that makes a graven image and bows down to it.” It is significant that I back this view up because if you ask a CM how they would translate the verse they will take the word לָמו as if it were referring back to both the “god” and the “idol” or to “Idols” and pluralize it while saying “see it is plural after all. Honestly, as a Jew who studies Hebrew Grammar, I don’t feel that that is quite 100% accurate but I do admit it is possible to read it as the CM’s are reading it.
Why I think לָמו reads as singular in Isaiah 44:15:
The first argument I encountered was that פֶסֶל should be considered a compound singular meaning that it can be singular but intend a plurality much like the Hebrew word עַם "people” functions as in Hebrew. The problem with this view is that it the primary usage of the word doesn’t have this compound singular reading. In fact, this word has verifiable usages of the plural to represent the plural in a number of cases such as Deuteronomy 7:5, 25; 2 Chronicles 33:19, 34:7; 2 Kings 17:41 and so on[i].
למו. כמו לו או כמשמעו (להם), ופי' לפסילים אף על פי שלא זכר אלא אחד רבים הם:
למו Lamo: Like “To him לו” or literally such (some versions read “literally to them”)[ii], The interpretation is “idols פסילים” even though it is only mentioned in the singular, it is plural in reference.
The RaDaK knew exactly what was going on here and to rightly say that in this case Lamo למו is equivalent to “לו.” His sticking point is the interpretation and the lack of using P’silim פסילים with a prepositionל that has a seemingly plural suffixםו which is why he said what he did at the end of this comment.
You also have to contend with the Targum's view and translation of this verse and how it views the reference as singular as well.
Targum Yonatan to Isaiah 44:15:
וֶהֱוֵי לֶאֱנָשָׁא לְאַדְלָקָא וּנְסֵיב מִנְהוֹן וּשְׁחֵין אַף אֲזָא וְאָפָא לְחֵם אַף עָבְדֵהּ דַחֲלָא וּסְגֵיד אִתְּכֵהּ צַלְמָא וּבְעָא מִנֵהּ
The last little part in question of 44:15 in the targum translates as "He makes an idol god and worships it, he forms/casts an image and beseeches from it" The preposition מִנֵהּ has a third person singular suffix ה attached to the preposition מן meaning "From Him/It." This tells us the Targumist saw this as a singular reference when he wrote the Targum.
In my opinion, I would translate Isaiah 44:15 as singular. Evidence from Chazal can lead us to either path of reading whether Singular or plural based on the Commentators and the view of the Targum.[iii]
Is לָמו in Isaiah 53:8 plural or singular?: