Lord Krishn sings in Bhagavad Gita:

“The yogi who is firmly devoted to me,
and
who constantly remembers me and is absorbed in me,
realizes me with ease.”

Sri Krishn is easily attained to by the worshiper who has no one except him in his mind,
and
who thinks steadily only of him and always remembers him.

HE adds:

“Accomplished sages who have attained
to
the ultimate state are no longer subject to transient rebirth
which is like a house of sorrows.’’

It is only after attaining to the Supreme Spirit that man is not born again.
Lord Krishn then speaks of the sphere of rebirth.

“All the worlds from Brahmlok downwards are, O Arjun,
of
a recurrent character, but, O son of Kunti,
the soul which realizes me is not born again.”

The conception of different worlds ( lok )
in sacred books is an exercise in the creation of metaphor.
There is no dark pit in the nether world
in which we are stung and tortured
by
venomous creatures called hell,
nor is there a domain in the sky which we call heaven.

Man himself is a god when he is imbued with pious instincts
and
he, too, is a demon when overtaken by impious impulses.
Men, gods, and sub-humans constitute the three metaphorical worlds.
Lord Krishn insists that the Self,
carrying with himself the mind and the five senses,
assumes new bodies according to the sanskar
earned over innumerable lives.

Gods, embodiments of virtue, whom we call immortal, are also subject to death.
And there can be no greater loss than the destruction of piety in this mortal world.
What is the use of this godlike body if it works for the destruction of the earned righteousness?

All the worlds, from the highest to the lowest, are worlds of suffering.
Man alone can shape the action by which he achieves the supreme goal,
after which there is no recurrence of birth and death.
By the ordained action man can become God
and
even achieve the position of Brahma himself, the first deity of the sacred Hindu Trinity
to whom is entrusted the task of creation.
And yet he will not be spared from rebirth until,
with restraint and dissolution of the mind,
he perceives God and merges into him.
The Upanishads reveal the same truth.

According to the Kathopanishad,
the mortal human is capable of being immortal and,
within this physical body and in this world itself,
he can achieve direct perception of the Supreme Spirit
by the destruction of all attachments of the heart.