Everlasting hyms , vedas, Upanishads known as vedic literature is taught by recitation.This is to become aware of the Lord and follow the path towards salvation..
The question that arises then is how do we contemplate on the Lord if we do not know his Eternal form?
Those ancient siddha purushas knew the path to realising God and were aware of His eternal form and nature. But they do not exist now and hence we cannot receive their instructions and insights..But those people who were aware of His being were delighted and bathed in bliss of supreme knowledge and have given us glorious hymns and praises on the Lord they were most aware of.
If we follow their path/ teachings and practice the deeds in earnest there is no doubt that our life will be more meaningful and worthwhile.