This tree of worldly existence is so tangled that we cannot see its true form. We cannot find where it begins, where it ends, or what holds it in place. It is like an ancient banyan tree whose original root is impossible to trace — the aerial roots have dropped everywhere, new trunks have sprouted, and the whole thing is a web of growth upon growth.
So Krishna says: do not keep trying to analyze it endlessly. There is one thing to do — cut it down. And the weapon for this task is vairagya, non-attachment. Not a dull sadness or withdrawal from life, but a firm, sharp instrument.
Just as a farmer needs a sharp sickle to harvest a standing crop, the seeker needs firm inner resolve to sever attachment. The word used is dridhena — with strength. This is not passive resignation. It is a deliberate, decisive act.