In Volume 2 Part 1 of The Christian in Complete Armor, which is about the shield of faith, William Gurnall lists the properties of true faith as being 1) obediential 2) prayerful and 3) uniform.

In the section about the property of faith being prayerful, Gurnall writes that “Prayer, it is the child of faith; and as the child bears his father’s name upon him, so doth prayer the name of faith.  What is it known by but by ‘the prayer of faith?’ James 5:15.” He says that prayer is the very natural breath of faith. The 2 parts of prayer, supplication and thanksgiving, both require faith.

First, supplication — praying to God and making your requests known to Him — requires faith because, “he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.” (Hebrews 11:6) So when you pray, you are showing that you believe God exists and that He will hear you and answer you.

The 2^nd part of prayer, praise, also requires faith. David’s heart had to be fixed on God before he could sing and give thanks. Gurnall says that thanksgiving is an act of self-denial. So when you are praising God, you are showing that you believe God has answered your prayer and that your blessings are from Him. You are giving God the glory. Gurnall says that “as the creature cannot pray—I mean acceptably—without faith, so with faith he cannot but pray.”

Since supplication and praise both require faith, you can see how prayer is the natural outflow, or breath, of faith. You believe that God is there and that He loves you, so you pray to Him and make your requests known to Him, and then you praise Him for His blessings to you.

Gurnall says that in the same way that by a double motion we breathe air into our lungs and then exhale it out, as Christians we draw in mercy from God and then breathe back that mercy to Him in praise. So you can try using that imagery during a meditation time. Breathe in mercy, breathe out praise to God. When you breathe in, think about the promise of eternal life –  that your sins have been forgiven, that you have the hope of heaven. And when you breathe out, breathe out your grateful praises to God for all of His mercies to you.

Here is a link to The Christian in Complete Armor: The Christian