Which preposition to use with bour

for Occurrences 1%

As my poor mo-ther gets weak-er, I should work for her; and as I grow in-to a man, she should not work any more, but sit by the fire and get the din-ner rea-dy, which I shall then be a-ble to la-bour for.

on Occurrences 1%

Sleep, then, in peace, that you may rise pre-pa-red for la-bour on the com-ing morn."

Which preposition to use with  bour