Sutra:
18. ithu thAn * kulantharum * engiRapadiyE ellA abEkshithankaLaiyum kodukkum.

Meaning:
This Thirumanthra will give that which is seeked by devotees, as told by Thirumangai Azhvar in his pasuram "kulam tharum ...".

Sri PBA Swami's Sarartha Deepikai:
The greatness of the Thirumanthra is further explained by the fact that it will provide to those who recite it what they seek.

Thirumangai Azhvar's pasuram goes thus:
kulantharum selvam thanthidum adiyArpadu thuyarAyinavellAm
nilantharanjseyyum nILvisumbaruLum aruLodu perunilamaLikkum
valantharum maRRum thanthidum peRRathAyinumAyina seyyum
nalantharunjsollai nAnkAndukoNdEn nArAyaNAvennum nAmam

The meaning of this pasuram is: the Narayana nama will give to those who recite it, a high class, wealth, it will destroy all that cause suffering to His devotees, it will give them mOksha, it will provide them His grace and the strength to remain in His anubhava, and give all good things that are seeked by them.

Thus, the Thirumanthra will provide all the good things that are seeked by those who keep reciting it.