The "KIlakam" or The peg or pillar that supports mantra to make it strong

अहं त्वा सर्वपापेभ्यो मोक्षयिष्यामि मा शुचः।।18.66।।

ahaṅ tvā sarvapāpēbhyō mōkṣayiṣyāmi mā śucaḥ..18.66..

The blessed Lord supports you by promising "Don't grieve ! , I will liberate you from all sins ."

This is the pivot around which the upadesha revolves.

say no more :)