Sutra:
38. SamSArikaLukku virOthi sathrupeedAthipathikaL, abEkshitham anna pAnAthikaL; mumukshukkaLukku virOthi SamSAra Sambantham, abEkshitham paramapatha prApthi; muktharkkum nithyarkkum virOthi kainkaryahAni, abEkshitham kainkaryavruththi.

Meaning:
For SamSAris, the problems that come from their enemies are the obstacles while things like food and water are what they seek. For Mumukshus who want to break from the SamSAric misery, staying in this world is the obstacle while being with Him in SriVaikuntam is what they seek. For Muktas and Nithyasooris, anything that can cause a break in their service to Him is the obstacle while uninterrupted continuance of their service to Him is what they seek.

Sri PBA Swami's Sarartha Deepikai:
Here the obstacles and goals seeked by the different classes of souls are explicity explained.

Those who think that their body is everything and do not even consider that there is something as a soul inside that body and are forever immersed in worldy matters are Baddha SamSAris. The obstacles faced by them are the problems caused by their enemies and problems due to diseases of the body and the mind. The things that they seek to get are food, water, etc. Thus the protection of such souls is removing these obstacles and providing them food and water.

Those who find SamsAra a source of misery (iruL tharumA nyAlaththuL ini piRavi yAn vENdEn, AthalAl piRavi vENdEn) and wishing to have nothing more with this world (thAvi vaiyam koNda thadanthAmaraikatkE kUvik koLLum kAlAm innam kuRukAthO) seek to reach His abode (nalamanthamilAthathOr nAdu) are known as Mumukshus. To them being in this world with this body (poy ninRa nyAnamum pollAvozhukkum azhukkudambum) is the obstacle. Being with Him and enjoying Him endlessly is what they seek. Therefore, the protection of mumukshus is removing the SamSAra bhanda and giving paramapada prApti.

The muktAs are those who have been in the SamSAra bhanda for a long time but have broken from it (vinai paRRaRukkum) and have reached His abode. The nithyasUris are those who never leave Him and are forver at His abode in His service (ozhivil kAlamellAm udanAy manni vazhuvilA adimai). To them both, anything that interrupts their service at His lotus feet is the obstacle and what they seek is the uninterrupted continuance of that service (kainkaryAbhivrutti).

Thus, as He removes obstacles and provides what everyone seek, based on their status, He is known as sarva rakshaka.