Though an unbeliever sin in praying, yet it is not a sin for him to pray. There is sin in the manner of his praying; but prayer, as to the act and substance of it, is his duty. He sins, not because he prays, that is required of him, but because he prays amiss, not in that manner that is required of him. There are abominations in the prayers of a wicked man, but for him to pray is not an abomination, it is the good and acceptable will of God, that which He commands.

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When we pray, the circumstances often remain the same, but we become different.
Oswald Chambers

Prayer does not change God, but the one who prays.
Søren Kierkegaard

Courage is fear that has said its prayers.
Corrie ten Boom

To pray is to draw breath from God.
Dietrich Bonhoeffer

You can do more than pray after you have prayed, but you can never do more than pray before you have prayed!
Charles Haddon Spurgeon

Prayer does not equip us for greater works – prayer is the greater work.
Oswald Chambers

God has his ear at your heart.
Augustine of Hippo

Prayers are tools not for doing or getting, but for being and becoming.
Eugene Peterson