Sutra:
25. vAcakaththiRkAttil vAcyaththilE oonRukaikku adi IsvaranE upAyOpEyamenRu ninaiththirukkai.

Meaning:
Previously it was shown that the Thirumanthra (vAcakam) is greater than the Lord (vAcyan) of whom it speaks about. Then, why were our acharyas attached so much to Him rather than to just the Thirumanthra?
Our acharyas did not seek to attain certain things using the Thirumanthra, or use other means to a certain end while keeping the Thirumanthra as supporting means. They considered only Him as both the means (upAya) and the end (upeya).

Sri PBA Swami's Sarartha Deepikai:
In the previous sutras, the importance and power of the Thirumanthra were greatly talked about. It was said that that the Thirumanthra helps bring about things that are seeked; also that it helps support and complete the Karma, Gnyana and Bhakti yoga paths.

As the Thirumanthra has such greatness, why doesn't everyone simply be immersed in it alone - instead, why are our acharyas so deeply attached to Him who is spoken by the Thirumanthra?
It is because of the following reasons. There are many that use the Thirumanthra as the tool to obtain certain things that they seek. Others seek Him as the goal and use the Karma, Gnyana and Bhakti yogas while using the Thirumanthra as a supporting tool in their path. Our acharyas are unlike either group. They only consider Him as the means as well as the goal. As such, they are greatly attached only to Him (vAcya), who is spoken by the Thirumanthra (vAcaka), rather than on the manthra itself.

Till this sutra, the greatness of the Thirumanthra was explained by Sri Pillai Lokacharya. From here on, he begins to explain the meanings of the manthra.