Thirukkural-On Virtue-Truthfulness-Kural-299

This again is Rajaji's translation, which cannot be bettered.

Lamps do not give the light that holy men desire; It is the light of truth that illuminates their path.

To light the path of men of virtue ordinary lamps will not suffice; only the Truth can serve the purpose. The expression 'Poiyaa Vilaku' means the light that does not fail, unlike the sun, moon and fire, all of which do not dispel ignorance. Only truth does that and hence it is the unfailing light. 'The truth shall make you free' (St. John 8:23).

Cardinal Newman's famous lines of 'Lead Kindly Light' were addressed to “God, the embodiment of Truth, to guide his path 'amidst the encircling gloom'.

'Thandialangaram' has an expressive passage bringing out the same sense as follows:

Vengadhirkkum senthiviri sudarkkum neengaadhu
Pongu madhiyolikkum poagaadhu
Thangum valamaiyaan vandha madhi marutki
Maandharkilamaiyaan vandha irul

(Thandi-49)