There is a wonderful commentary on this by Sri Aurobindo in the Isha Upanishad writings as well as Isavasyaupanishad. There is also a whole talk on the Isha Upanishad.
It is a must read Upanishad if one wants to know the foundation of Indian spiritual culture.
In brief it means that the will to appropriate things for oneself springs from the desire self (and leads inevitably to the duality of pleasure and pain). But what we should know is that everything belongs to the Lord. Today it is with us, given to us. Tomorrow it will be taken away and with someone else. When we become aware of this truth then we renounce attachment (tyaga and not sannyas) even while being in the world. We are like the Lord’s trustees who must care well about everything because it is the Lord but inwardly be free of all sense of possession and ownership. When we thus lead our life we share in the delight of the Divine and thereby do not covet anything anymore.
Affectionately,
Alok Da
