You deem yourself by virtue of your asceticism incapable of being destroyed by the celestials and Asuras; and herein your great merit (incident to they austerities) is the cause.
अवध्यतां तपोभिर्या भवान् समनुपश्यति। आत्मनः सासुरैर्देवैर्हेतुस्तत्राप्ययं महान्॥