expression
now, let us go; let's go
A formal or literary expression used to rally or announce departure, often with a dramatic or resolute tone. The 行かん is an archaic volitional form (equivalent to modern 行こう).
いざ行かん、戦いの地へ。
Now, let us go to the battlefield.
準備は整った。いざ行かん!
Preparations are complete. Let's go!