[Er.sandeep jain]

If the substance (dravya) is not of the nature of existence – i.e., if it is not sat – then its permanence (dhruvatva) must become nonexistent – asat. How can something that is non-existent – asat – be a substance (dravya), or how can a substance (dravya) exist – remain as sat – without the nature of existence? Therefore, the substance (dravya) is of the nature of existence – it is sat. 

Explanatory Note: 
If the substance (dravya) is not of the nature of existence – if it is not sat – two anomalies arise: 1) the substance (dravya) must become non-existent – asat, and 2) it must become discrete from the nature of existence – i.e., sat. If the substance (dravya) becomes non-existent – asat – it must lose permanence and face destruction. If the substance (dravya) becomes discrete from the nature of existence – i.e., discrete from sat – it must carry on with its own nature, without the nature of existence – i.e., sat.
In this case, the nature of existence – i.e., sat – becomes superfluous and, under such a hypothesis, the nature of existence – i.e., sat – itself loses its existence. Only when the substance (dravya) has existence – i.e., sat – as its nature, will it become permanent (dhruva) and indestructible. Only when the substance (dravya) is not discrete from its nature of existence – i.e., sat, will it be able to exist in own nature, establishing thereby the nature of existence – as the sat. Therefore, the substance (dravya) is of the nature of existence – it is sat. The substance (dravya) is the possessor-of-quality (gunī) of the quality (guna) of existence