Mr. Halliwell, in his _Dictionary of Archaic and Provincial Words_, vol.
ii. p. 724., thus explains this phrase:
"The Deity is mentioned in the _Towneley Mysteries_, pp. 97. 118., as
He that 'sett alle on seven,' _i. e._, set or appointed everything in
seven days. A similar phrase at p. 85. is not so evident. It is
explained in the Glossary, 'to set things in, to put them in order;'
but it evidently implies, in some cases, an exactly opposite meaning,
to set in confusion, to rush to battle, as in the following examples.
'_To set the steven_, to agree upon the time and place of meeting
previous to some expedition,'--_West and Cumb. Dial._ p. 390. These
phrases may be connected with each other. Be this as it may, hence is
certainly derived the phrase _to be at sixes and sevens_, to be in
great confusion. Herod, in his anger at the wise men, says:
"'Bot be they past me by, by Mahowne in heven,
I shalle, and that in hy, _set alle on sex and seven_;
Trow ye a kyng as I wyll suffre thaym to neven
Any to have mastry bot myself fulle even.'
_Towneley Mysteries_, p. 143.
"'Thus he _settez on sevene_ with his sekyre knyghttez.'
_Morte Arthure_, MS. Lincoln, f. 76.
"'The duk swore by gret God of hevene,
Wold my hors so evene,
Zet wold I _set all one seven_
Ffor Myldor the swet!'
_Degrevant_, 1279.
"'Old Odcombs odnesse makes not thee uneven,
Nor carelesly set all _at six and seven_.'