Nidhi means treasure and avyayah means everlasting or indestructible. The Lord is the permanently inexhaustible treasure for his devotees/bhaktas. Any of the physical treasure of this world are always limited and exhaust in due course of time. But, Lord is the everlasting treasure.
paras tasmat tu bhavo ‘nyo ‘vyakto ‘vyaktat sanatanah
yah sa sarvesu bhutesu nasyatsu na vinasyati (BG 8.20)
Yet there is another nature, which is eternal and is transcendental to this manifested and unmanifested matter. It is supreme and is never annihilated. When all in this world is annihilated, that part remains as it is.
The Lord clearly states is the only one who is permanent, and all other living and non-living entities have a time span and would perish eventually.
Lets chant the Holy Name and ensure this perishable life of ours is always in the service of the Supreme Lord Krishna.
Nama 30 – VishnuSahasranama