Adam Clarke on Isaiah 55:9

For as the heavens are higher - I am persuaded that כ caph, the particle of comparison, is lost in this place, from the likeness of the particle כי ki, immediately preceding it. So Houbigant and Secker. And their remark is confirmed by all the ancient Versions, which express it; and by the following passage of Psa 103:11, which is almost the same: - הארץ על שמים כגבה כי haarets al shamayim chigboah ki יראיו על חסדו גבר yereaiv al chasdo gabar "For as the heavens are high above the earth,

So high is his goodness over them that fear him."

Where, by the nature of the sentence, the verb in the second line ought to be the same with that in the first; גבה gabah, not גבר gabar: so Archbishop Secker conjectured; referring however to Psa 117:2.