As Shared By Swami Sivananda:
The obstacles to meditation are only from within.
Sleepiness, passions, confused state of the mind,
Manorajya (building castles in the air) are the
chief obstacles that stand in the way of fixing
the mind on God or Brahman. The five hindrances
to meditation, viz., sense-desire, ill-will,
sloth-torpor, flurry-worry and perplexity should
be removed. For, when these are not removed,
meditation cannot arise. The mind that lusts after
many things through sense-desire is not concentrated
on one object; or being overcome by sense-desire,
it does not enter upon the progress of meditation
in order to put away the sensuous element. The mind
that is harassed by ill-will concerning an object
does not proceed at once. The mind that is overcome
by sloth and torpor is unwieldy. Obsessed by worry
and flurry, it does not repose, but flirts about.
Struck by perplexity, it does not go on the path that
leads to the attainment of meditation and Samadhi.
Obstacles to meditation are thus really from within.
They are not from without. Train the mind properly.