Charles Ellicott Commentary Psalms 106:23

"Therefore he said that he would destroy them, Had not Moses his chosen stood before him in the breach, To turn away his wrath, lest he should destroy [them]." — Psalms 106:23 (ASV)

Stood before him in the breach ... —This is generally explained according to Ezekiel 22:30, where it is undoubtedly an image taken from the defense of a besieged town. (Compare to Ezekiel 13:5.)

However, it is possible that we should translate it as, “Had not Moses stood before him (i.e., submissively; Deuteronomy 1:38) in the breaking forth (of his anger),” since the verb from which the noun used here comes is the one employed in Exodus 19:22: lest the Lord break forth upon them.

The Septuagint translators also seem to have understood the passage this way, since they render it here with the same word that, in Psalm 106:30, serves for “plague.” (Compare to Vulgate, refractio.)