Sutra:
148. iththAl pirAttikku iruppidamAy guNaprakAsagamumAy sisubAlanaiyumagappadath thiruththis sErththuk koLLum thirumEniyai ninaikkiRadhu.

Meaning:
The divine feet are one part of His divine form. In talking about this part, His entire divine form (divya mangaLa vigraha), which is the residence of Sri Mahalakshmi, which clearly shows His divine qualities and which has the nature of capturing even those such as Sisupala whose habit is to abuse Him, is explained.

Sri PBA Swami's Sarartha Deepikai:
The point about His divine feet implies the same for His divine form. In speaking about the one part (feet), His whole divine form is thought of. This divine form is the residence of the mediatrix Sri Mahalakshmi. The divine qualities shown through the nArAyaNa term shine in it. It corrects even Sisupala who abused Him in many ways and accepts him ("sEtpAl pazham pagaivan sisupAlan, thiruvadi thAtpAl adaintha").