Secret prayer...

-Spurgeon, 'Paul's First Prayer'

Secret prayer
is one of the best tests of sincere religion.
He who prays in private is a real Christian.
The mere reading of a book of daily devotion will not
prove you a child of God; if you pray in private, then you
have a sincere religion.

A little religion, if sincere, is better than mountains of pretense.

Home piety is the best piety.

Praying will make you leave off sinning,
or sinning will make you leave off praying.

Prayer in the heart proves the reality of conversion.
Now, with all the solemnity that man can summon,
let me say that a prayerless soul is a Christless soul.
You who never know what a groan is, or a falling tear,
are destitute of vital godliness.