Ibn Ezra, on Isa 56:2

“Blessed is the man that doth this, and the son of man that shall lay hold on this: that keepeth the sabbath from profaning it, that keepeth his hands from doing any evil.”

“Blessed is the man that does this, that keeps the following precepts, to observe the Sabbath, etc. מחללו From polluting it. It is certain that the ת in שבת indicates the feminine gender; the masculine pronoun וֹ refers to the masculine noun יום day, which may be supplied before שבת, or to the verbal noun שִׁמּוּר implied in the verb שֹׁמֵר; for every verb implies a verbal noun, if that is not directly expressed; compare the remark of R. Moses Hakkohen on וַתִּצְפְּנוֹ (Jos. 2:7), that the suffix refers to the verbal noun the taking; compare also ברב יעצים עצה תקום ═ ברב יעצים תקום, in the multitude of counsellors it is established (Prov. 15:22), the word עצה being supplied.”

Imported from an open dataset — not yet checked against the printed edition.