Adam Clarke on Isaiah 63:3

And of the people there was none with me - I was wholly abandoned by them: but a good meaning is, No man has had any part in making the atonement; it is entirely the work of the Messiah alone. No created being could have any part in a sacrifice that was to be of infinite merit.

And I will stain "And I have stained" - For אגאלתי egalti, a verb of very irregular formation, compounded, as they say, of the two forms of the preterite and future, a MS. has אגאלהו egalehu, the regular future with a pleonastic pronoun added to it, according to the Hebrew idiom: "And all my raiment, I have stained it." The necessity of the verb's being in the past tense seems to have given occasion to the alteration made in the end of the word. The conversive ו vau at the beginning of the sentence affects the verb, though not joined to it; of which there are many examples: - anithani remim umikkarney עניתני רמים ומקרני "And thou wilt hear me (or hear thou me) from among the horns of the unicorns," Psa 22:22. - L.

Instead of על בגדי al begadai, upon my garments, one of my ancient MSS. has לארץ בגדי larets begadai, to the earth: but this word is partly effaced, and על al written in the margin by a later hand.