Arthur Peake's Commentary on the Bible
Psalms 56 - Introduction
BOOK II. PSS. XLII.- LXXII.
Psalms 42-83 are Elohistic, i.e. they use the word God (Elohim) and avoid the proper name Yahweh, probably from motives of reverence. Here and there, however, the name Yahweh has crept into the text by a natural slip of the scribes.