Theophan the Recluse (1815 – 1894 CE) is a saint of the Orthodox church. He was the son of an Orthodox priest, became a monk as a young man, and later served as the Bishop of Tambov. One of his works was to translate the Philokalia, a collection of writings emphasising the path of constant inward prayer, from Church Slavonic into modern Russian.

You must descend from
your head into your heart.
At present your thoughts of God
are in your head. And God Himself is,
as it were, outside you, and
so your prayer and other spiritual
exercises
remain exterior. Whilst you are still
in your head,
thoughts will not easily be subdued but
will always be whirling about, like snow
in winter or
clouds of mosquitoes in summer.