I've found this sentence
and I'm trying to understand what it means. Searching on Google, it seems that ざらんや belongs to Kobun language and is paired with 敢へて as explained here.
According to this website, it is also told that 敢へて～ざらんや can be interpreted as「どうして～しないことがあろうか、いや必ず～する」. However, I must say I don't understand either this interpretation in modern language, so the meaning of
is still not clear to me. Could you please explain to me 敢へて～ざらんや and 「どうして～しないことがあろうか、いや必ず～する」and tell me the meaning of this sentence?
Besides, is ～ざらんや always paired with 敢へて, so that I will always see it as 敢へて～ざらんや, or can it be used alone as well? If so, how would its meaning change from 敢へて～ざらんや?