The Self is the witness, all-pervading, complete and full, singular, liberated. It is consciousness and hence non-acting. It is un-associated, absolutely desire-free, quiescent, peaceful. Only due to delusion, it appears to be worldly.
The sage again reiterates the characteristics and qualities of the Self so that Janaka and others like him will go on reflecting upon them repeatedly. The Self is always the witness. By its very nature it is the subtlest and hence all-pervading.
The Self being singular, there is no question of it getting conditioned or affected adversely by any other entity. Being alone and singular, anything will become free and liberated. Bondage and conditioning will arise only when there is a second factor present alongside.
The same applies to attachment or association. Self is totally unaffected, un-associated. There is no question of the Self desiring anything at all, because there is nothing to be desired and it is full by itself. It is peaceful to the core. It appears to be worldly, performing actions etc. only through the power of illusion. There is no activity at any point taking place in the Self. Therefore it is free, full, and quiescent.
While the whole world and its objects are inert matter, the inner immutable presence is pure Consciousness itself. It only makes you conscious of other things as well as yourself. It does not become anything. To think of it as anything else is a sheer illusion.