Below is an excerpt of Modesty: More than a Change of Clothes by Martha Peace & Kent Keller, pages 17-18.

What Is the Biblical Standard of Modesty?

A picture book would have been quite handy, but God chose in His infinitely perfect wisdom to give us words to answer this question. After all, the Scriptures were written “for our instruction” (Romans 15:4). The Bible tells us what we are doing wrong, teaches us how to correct it, and trains us to be godly (see 2 Timothy 3:16).

Based upon the Bible as revealed in the chapters that follow, this is our definition of modesty:

Modesty is an inner attitude of the heart motivated by a love for God that seeks His glory through purity and humility; it often reveals itself in words, actions, expressions, and clothes.

If you have a heart(1) that loves God, you will want to please God. According to the Bible, the heart is the part of you that thinks your thoughts, makes the choices of your will, feels your emotions, and lives on after your death.

A heart that is concerned about pleasing God will express itself modestly by what you think, say, do, and wear. True modesty can come only from someone who is more concerned about showing the world how great God is than how great she is. True modesty doesn’t come from changing one’s wardrobe. It comes from having one’s heart changed. If you want to be modest, your heart must follow after God. When you choose to be immodest (or commit any sin), then you are choosing your own sinful desires over God’s desires, showing that He is not first in your life—at least not at that moment.

God can again be first in your heart when you repent from your sin and believe in His Son Jesus Christ (Mark 1:15). Repenting from sin means that you change your view of sin so that you live as God desires. What used to seem fun or desirable is now seen as something that God hates, so you want to turn from that sin. God is first in your heart when you believe that Jesus is the only one who can save you from your sin. He is the Lord and Master of your heart. When He is most important to you, you want to please Him by doing what He commands, because you love Him! When God is first in your heart, you will be modest!

On the other hand,

Immodesty is an attitude of the heart that expresses itself with inappropriate words, actions, expressions and/or clothes that are flirtatious, manipulative, revealing, or suggestive of sensuality or pride.

Just as with modesty, the immodesty we can see comes from an immodest heart, which we can’t see. You can, however, measure the heart by the fruit that your life produces (Matthew 7:20). If you want to act or dress immodestly so that you catch the attention of all the guys, or at least that cute one who you wish would pay more attention to you, God is not first in your heart.

If you haven’t found out already, some guys can be manipulated pretty easily. This desire to get them to do what you want by flirting, behaving, or dressing immodestly does not honor God. This does not come from a pure heart, but from a sinful desire for attention that dishonors God.

(1) When the Bible refers to the “heart,” it never refers to the phys- ical organ that pumps the blood around in one’s body. Neither לב (leb) in the Old Testament nor καρδια (kardia) in the New Testament ever refers to the physical organ.