According to the Ashtavakra Samhita, it is the mind that is responsible for one’s sense of freedom or bondage:
‘He who considers himself free is free indeed, and he who considers himself bound remains bound.’
The popular saying “As one thinks, so one becomes” is true indeed.’ (Ashtavakra Samhita 1.11)
We have an explanation in Sri Ramakrishna’s words:
The mind is everything. A man has his wife on one side and his daughter on the other. He shows his affection to them in different ways. But his mind is one and the same.
Bondage is of the mind, and freedom is also of the mind. A man is free if he constantly thinks, ‘I am a free soul. How can I be bound, whether I live in the world or in the forest? I am a child of God, the King of Kings. Who can bind me?’ … by repeating with grit and determination, ‘I am not bound, I am free’, one really becomes so – one really becomes free.
Swami Vivekananda says
You must always remember that each word, thought, and deed, lays up a store for you and that as the bad thoughts and bad works are ready to spring upon you like tigers, so also there is the inspiring hope that the good thoughts and good deeds are ready with the power of a hundred thousand angels to defend you always and forever.