The specific qualification for becoming the representative of the Lord is to be unaffected by the material modes of nature. The highest qualification of a person in the material world is to be a brahmana. But since a brahmana is in the mode of goodness, to be a brahmana is not sufficient for becoming a representative of the Lord. One has to transcend the mode of goodness also and be situated in unalloyed goodness, unaffected by any of the qualities of material nature. This stage of transcendental qualification is called suddha-sattva, or vasudeva, and in this stage the science of God can be realized. As the Lord is not affected by the modes of material nature, so a pure devotee of the Lord is also not affected by the modes of nature. That is the primary qualification for being one with the Lord. A person who is able to attain this transcendental qualification is called jivan-mukta, or liberated, even though he is apparently in material conditions. This liberation is achieved by one who constantly engages in the transcendental loving service of the Lord. In Bhakti-rasamrta-sindhu (1.2.187) it is stated: