109. kaNNArak kaNdu kazhivathOr kAthaluRRArkkum uNdO kaNgaL thunjsuthal enkiRapadiyE kANbathaRku munbu uRakkamillai; kaNdAl *SathA pacyanthi* AgaiyAlE uRakkamillai.
Before seeing Him, as told by Azhvar, there is no sleep; after seeing Him, as told by the Upanishads, there is no sleep.
Sri PBA Swami's Sarartha Deepikai:
Previously the entreaty to perform service was explained. Here the nature of those who make that prayer forever, is explained.
As in "imaiyOrkaL kuzhAm thozhuvathum sUzhvathum sey thollaimAlaik kaNNArak kaNdu kazhivathOr kAthaluRRArkkum uNdO kaNgaL thunjsuthalE", for those who seek His service, there is no sleep prior to seeing Him. After seeing Him, as said in the Upanishads, "tat vishNO: paramam padam sadA pashyanti sUraya:", the seeing experience is eternal and therefore there is no sleep.
That is, for those who have developed the taste to reach Him, there is no sleep ever.