You see in the world a reflection of your notion of self

If one thinks "I am this body" one sees other bodies. If one thinks "I am the mind", then one sees other minds. If one knows one is the Self, then there is no other. All is the Self.

For this to become permanent the outgoing tendency of the mind has to permanently subside. Until then sAdhanA is needed and intermittent samAdhi will be experienced.

Related: योग सूत्र १-२० श्रद्धा वीर्य स्मृति समाधि प्रज्ञा पूर्वक इतरेषाम् Yoga sUtra I.20 shraddhA vIrya smRti samAdhi prajnA pUrvaka itareshAm.
For the rest (those who are embodied), faith, energy, memory (of the Truth), samAdhi, prajnA (Gnosis, the first knowledge, obtained by meditation when the mind recedes beyond the realm of dreams to the latent impressions or samskAras) are needed first.

In other words, for embodied jIva-s the path to the Self consists of proceeding with faith, energy, memory (of the Truth), and samAdhi to prajnA.