The Upanishads'...

It is indeed the mind that is the cause of men’s bondage and liberation. The mind that is attached to sense-objects leads to bondage, while dissociated from sense-objects it tends to lead to liberation. – Amrita-Bindu Upanishad

The Self that is subtler than the subtle and greater than the great is seated in the heart of every creature. One who is free from desire sees the glory of the Self through the tranquillity of the mind and senses and becomes absolved from grief. - Katha Upanishad

Dissolve the self in the supreme Self as the pot-space is dissolved in infinite space; then, as the Infinite be silent for ever, O sage! – Adhyatma Upanishad

Knowing that great and all-pervading Self by which one sees (the objects) both in the sleep and the waking states, the intelligent man grieves no more. - Katha Upanishad

Liberated from the grip of egoism, like the moon (after the eclipse), full, ever blissful, self-luminous, one attains one’s essence. – Adhyatma Upanishad

He who perceives all beings in the Self alone, and the Self in all beings, does not entertain any hatred on account of that perception. – Isavasya Upanishad

That which is consciousness alone which is all-pervading, which is eternal, which is all-full, which is of the form of bliss and which is indestructible, is the only true Brahman (infinite consciousness). – Varaha Upanishad

Whether the body perishes now or lasts the age of moon and stars, what matters it to me having Consciousness alone as my body ? What matters it to the sky in the pot, whether it (the pot) is destroyed now or exists for a long time. – Varaha Upanishad

Bondage is the imagination prompted by the desire for the eight powers. – Niralamba Upanishad

Man is bound by ‘mine’, but he is released by ‘not mine’. He should abandon all the thoughts relating to externals and so also with references to internals. O Ribhu, having given up all thoughts, you should rest content (in your soul) ever.” – Varaha Upanishad

Like the butter hidden in milk, the Pure Consciousness resides in every being. That ought to be constantly churned out by the churning rod of the mind. – Amrita-Bindu Upanishad

Being first in a state of changelessness and then thoroughly forgetting (even) that state owing to the cognition of the (true) nature of Brahman (infinite consciousness) – this is called Samadhi. – Tejo-Bindu Upanishad

In order to realize the Self, renounce everything. Having cast off all (objects), assimilate yourself to that which remains. - Annapurna Upanishad

When all longings that are in the heart vanish, then a mortal becomes immortal and attains Brahman (infinite consciousness) here. - Katha Upanishad

Those who are clever in arguments about Brahman, but are without the action pertaining to Brahman (infinite consciousness) and who are greatly attached to the world – those certainly are born again and again (in this world) through their Ajnana (ignorance). – Tejo-Bindu Upanishad

As rivers, flowing down, become indistinguishable on reaching the sea by giving up their names and forms, so also the illumined soul, having become freed from name and form, reaches the self-effulgent Supreme Self - Mundaka Upanishad

... from spiritquotes.com