Krishna says that He is the Lord of everything. Everything comes from Him - material and spiritual and somebody who knows this engages full time in His devotional service. Then,
jnatva mam santim rcchati [Bg 5.29]
Krishna is the original beneficiary of all sacrifices and He is the owner of verything and he is the best friend. Knowing this one attains peace.
yo mam evam asammudho
sa sarva-vid bhajati mam
sarva-bhavena bharata [15.19]
One who knows Krishna as the Supreme Personality of Godhead without doubting s the knower of everything and that person engages in His devotional
service and they attain the Supreme goal of life. So all this knowledge defines who Krishna is.
iti guhyatamam sastram
idam uktam mayanagha
etad buddhva buddhiman syat
krta-krtyas ca bharata [Bg 15.20]
This is the most secret part of the Vedic knowledge and Krishna says I am revealing it to you Arjuna because you are sinless. Anyone who understands
this becomes wise and his endeavours will attain perfection.
Therefore we have something that is extremely precious but we just have to realise how valuable it is. That is why we have class. That is why we come
together. But there are things that can destroy this. Krishna says:
isavasyam idam sarvam
yat kinca jagatyam jagat
tena tyaktena bhunjitha
ma grdhah kasya svid dhanam [Iso mantra 1]
He is the isavasya - the owner and controller of everything and he has set aside for every living entity their minimum needs. Knowing this one should take only the minimum and use everything else in the service of Krishna.
kurvann eveha karmani
jijivisec chatam samah
evam tvayi nanyatheto 'sti
na karma lipyate nare [Iso mantra 2]
One who works in this way can live for hundreds and thousands of years but they are never affected by the reactions of work. There are no reactions
because they are engaged in akarma. These are very profound verses of the Bhagavad-gita.
There was once a predator bird that swooped down and got a big fish out of a lake and it started flying but there were a thousand crows that saw this and
they started following the bird. The bird felt the other birds following it so it flew as high as it could but they followed. Then it flew as low as it could. They followed. Then it flew to the right, flew to the left and finally got exhausted and let go of the fish. When it let go of the fish all the other birds let the bird go and they went for the fish. Then the bird was sitting on the branch of the tree and he was thinking, "That fish was a real problem." This is our life. As soon as we take even one paisa of what was meant for Krishna beyond our minimum needs we get affected by the material nature.
In fact there is a very nice verse in the Bhagavatam seventh canto that says, "O my Lord because of lusty desires from the very beginning of one's birth the functions of one's senses, mind, body, religion, patience, intelligence, shyness, opulence, strength, memory and truthfulness are vanquished. So Prabhupada explains that the real sickness in the heart is kamam hrd-rogam [SB 10.33.39] It is lust. The successive desire to own and control things and exploit them for sense gratification. It is undoing us all in this material world.
phalam tyaktva manisinah
padam gacchanty anamayam [Bg 2.51]