B.G 2.17

But know that to be indestructible by which all this is pervaded. The destruction of this imperishable is impossible and beyond anyone's ability.

Gīta Bhāshya 2.17

The destruction of such everlasting principles is denied by using the word 'avinashina'. Its unchanging nature is highlighted by the word 'avyaya'.

What are those others (without destruction)? Those that are not bound by space, that are everlasting like the Vedas, are indicated by the word 'avinashina'. Their destruction through instrumentality is denied by using the word 'vinasham', i.e. destruction. The word 'avyaya', i.e. unchanging, is used to address such principles.

Gīta Tātparya 2.17

Destruction is of four types: destruction of the body, possession of misery, incompleteness, and non-being. Though other principles are imperishable in some dimensions, only the Lord is imperishable in all four dimensions. The space, time and qualities are the different dimensions. On all these dimensions, Lord Hari alone is complete with all auspicious qualities. The word 'tu' is used to qualify this speciality of the Lord.

Even though eternality is indicated for individual beings, all kinds of everlasting qualities exist in the Lord Vishnu alone. This is specified by using the word 'tu'.

"Impermanence, loss of the body, experience of suffering, and incompleteness—these four kinds of destruction are declared; the absence of these is always with Hari, but for all others, some forms of destruction do occur."

- states Mahavaraha Purana

"The space, time, and qualities are the different dimensions. On all these dimensions, Lord Hari alone is complete with all auspicious qualities; no other."

–states Paramashruti, the Vedic testimonial.