Dear Sri Kunjuppu ji,
I am not expert in translation but still let me make an attempt.
Even if we have eight thousand years of life, we will not see God Almighty (probably externally). The moment we sincerely start looking for him internally , He appears to us instantaneously like we see our own image in a mirror.
Probably it conveys the message of advaitha philosophy `Jeevatma and Parmatma are one and the same' Or probably Vishistadvaida philosophy of `Jeevatma can become Paramathma'
The above stanza is from Thirumoolar's Thirumandiram. Thirumoolar is the second poet after Saint Agastiar migrated from Mount Kailash to South India. His composition is a wonderful masterpiece in the Tamil Literature. He didn't go out to various places nor visited temples.His work is on Saiva Sidhantha Philosophy.
Thirumandiram is one of the twelve master pieces of Shiva Literature in Tamil.( Saiva Panniru Thirumurai).
The above stanza appears facing Lordess Vaishnavi at Tirumullaivayil, near Chennai. The founder of the temple Swami Anvanandaji (Late Sri Parthasarathi Iyengar) was a leading advocate of his times. His father late Sri Srinivasa Iyengar was President of Congress Party during freedom struggle. Mahatma Gandhi use to stay in their house when he visits Chennai. Before taking up sanyas, Parthasarathi Iyengar was Managing Director of an Insurance company.
This temple is quite different from other temples in Tamilnadu. There is no paid priest and all of us (Men or Women, Hindu or Muslim or Christian) can do pooja directly to the Devi. No Hundi in the temple and no money is accepted from devotees in front of God. No VIP treatment for anybody. Late Sri Santhanam of TVS group is a patron of the temple and during navarathri days (crowd use to be very large), Sri Santhanam use to come in the Q like any other devotee.
The idol was installed by Vallimalai Sri Sachidananda Swamigal (guru of Swami Anwanandaji) reciting few stanzas from Tiruppugazh. No agama sastras were fallowed for the installation. Vallimalai swamigal was neither an expert in Tamil nor well versed in music.(He was an assistant cook at Mysore Palace). Lord Subramanya's grace made him revive Arunagirinathar's Tiruppugazh. He composed music for Tiruppugazh and popularised at every nook and corner.
I learnt the above stanza only from the Vaishnavi temple
Details about the temple is available in the following website:
Sri Vaishnavi Shrine, Aavadi (Chennai)
எண்ணாயிரமாண்டு யோகம் இருப்பினும் கண்ணார் அமுதனை கண்டரிவாரில்லை உள்நாடி ஒளிபெற உள்ளே நோக்கினார் கண்ணாடி போல கலந்து நின்றானே