Langenscheidt, Der Große Muret-Sanders:
Pardon m <-s; no pl> [...]
2. obs. mil. keinen ~ geben
to give no quarter
Harper Collins German Unabridged Dictionary:
Pardon m or nt -s, no pl [...]
jdm kein(en) ~ geben (old)
to give sb no mercy
to give sb no quarter
Schemann / Knight, German-English Dictionary of Idioms:
kein Pardon geben · 1. 2. to show no mercy (to s.o.), to give s.o. no quarter
Rees, Cassel's Dictionary of Word and Phrase Origins
give/grant no quarter, to.
Not to concede any ground. Previously, 'give quarter' meant to spare the life of an enemy in one's power. Known by 1645. An old theory that 'quarter' referred to the share of a soldier's pay which would be claimed as ransom does not seem to stand up. Perhaps rather it refers to the quarters a prisoner would
have to occupy.
Röhrich, Lexikon der sprichwörtlichen Redensarten:
Kein Pardon geben: nichts entschuldigen, keine Gnade walten lassenhttp://www.worldwidewords.org/qa/qa-giv1.htm
Its possible also that to give quarters could refer to the need to provide prisoners with a place to stay, so that to give no quarter was a figurative way of saying take no prisoners.http://home.snafu.de/veith/voelker.htm
Nach den Artikeln 23, 25 und 28 der Haager Landkriegsordnung ist es verboten, [...] zu erklären, daß kein Pardon gegeben wird, daß heißt keine Gefangenen zu machen oder sich Ergebende oder auch Verwundete zu erschießen;http://www.icrc.org/ihl.nsf/0/23ded6c2ddc2407...
Instructions for the Government of Armies of the United States in the Field (Lieber Code). 24 April 1863.
Art. 60. It is against the usage of modern war to resolve, in hatred and revenge, to give no quarter. No body of troops has the right to declare that it will not give, and therefore will not expect, quarter; but a commander is permitted to direct his troops to give no quarter, in great straits, when his own salvation makes it impossible to cumber himself with prisoners.