I'm afraid "Ware tada shiru taru" doesn't make sense as a Japanese sentence. That's a widely-spread misreading of 吾唯知足 or "Ware tada taru wo shiru" as I wrote in my previous post. Search just "Ware tada shiru taru" or "Ware tada taru wo shiru" without Nobunaga on google, then you can get the result that the maxim/proverb is from Zen Buddhism and has nothing to do with Oda Nobunaga. (Actually, only the two sites I linked above say that that's Nobunaga's slogan.)
Incidentally, his battle-banner mark is 永楽通宝[eirakutsuuhou], and not 吾唯知足[Ware tada taru wo shiru]. You can see the banner on the