Sutra:
215. mAm.
216. SarvarakshaganAy unakkuk kaiyALAy unnisaivu pArththu un dhOshangaLai bOgyamgAgak koNdu unakkup pugalAy, neer sudumApOlE sErppArE pirikkumpOdhum vidamAttAdhE rakshikkiRa ennai.
217. iththAl paravyUhangaLaiyum dhEvthAntharyAmithvath- thaiyum thavirkkiRadhu.

Sri PBA Swami's Sarartha Deepikai:
Now the meaning of "mAm" is explained.

The Lord says 'mAm' refering to Himself - who is focused on protecting everyone; who can be made to do pleasing things for His devotees; who looks for approval by His devotees; who takes His devotees sins as pleasing acts (so they don't have to be afraid); who is the refuge for His devotees; who never gives up His devotees ("ennadiyAr adhu seyyAr") even if Periya Piratti, who normally mediates for them, were to point to their sins and ask that they be rejected ("thAmaraiyALAgilum sithag- uraikkumEl") and stands alone and protects them.

Since He, who has taken avatar in this world and is present in a form that is visible to everyone (vibhava), refered to Himself as 'mAm', it rejects His para and vyUha forms which are not visible being remote in space and His antharyAmi form being inside devatas such as agni and indra and being worshipped by those using other means. It also shows the difference of this form from them.