Many believers are shocked when they hear of a brother or sister entangled in sin. Yet these people were most likely struggling for years while the roots of sin were digging deep into their hearts. Sin has subtle beginnings in the hearts and minds of those who were unaware or demonstrate a laissez faire attitude about its impending damage. God gives us wisdom and insight in
Proverbs 4:23 with—
“Above all else, guard your heart, for everything you do flows from it.”
What does it mean to guard our hearts? In order to do so, we must be willing to take proactive measures so that we don’t fall into sin and lose our faithful testimony. Take the charge to G-U-A-R-D your heart with the following Bible study:
G – Guard your thoughts with due diligence
“Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ” (2 Corinthians 10:4, KJV).
Have you ever caught yourself imagining revenge or engaging in sin? It’s one of those traps our unfiltered thoughts can entertain. We must learn the discipline of screening our thoughts and silencing any imaginations which aren’t in line with Christ’s example of love. If we allow our thoughts to wander long enough, we set ourselves up to failure. Sin begins in the mind and the root of it can become a stronghold even in the lives of believers. Use your sword of the Spirit by cutting down wayward thoughts with 2 Corinthians 10:4-5.
Read 1 Corinthians 14:20, Philippians 4:8-9, and Hebrews 3:1-6. What are the characteristics of your thoughts? Are they holy or unholy? Begin to train your mind to be under the control of the Holy Spirit using the word of God.
Related reading: 5 Ways To Avoid Sinful Habits or Thoughts 
U – Understand that you need power from the Holy Spirit to deal with temptation
“But you will receive power when the Holy Spirit comes on you” (Acts 1:8).
Through the Holy Spirit every believer has power from God to overcome temptations  that cloud your thoughts and darken your heart. Our strongest fortress is recognizing that we are dependent on the Holy Spirit to guide us into all truth. Our hearts are desperately wicked and longing to please the flesh. Yet as we have communion with God through Jesus Christ, we can excel in our spiritual maturity and boldly represent the body of Christ without fear or shame. Simply ask in prayer for God’s power to guard your heart.
Read Job 9:1-13, 2 Timothy 1:7-10, and 2 Peter 1:3-11. How does the power of God give you strength to guard your heart? Pray and confess your dependence on God to overcome and guard your heart.
A – Allow for the influences of godly men and women to give advice
“The way of fools seems right to them, but the wise listen to advice” (Proverbs 12:15).
The body of believers aren’t individual islands, but rather we’re strategically connected living spiritual beings. We are to bear one another up in prayer, service, and support in order that every part of the body is spiritually healthy. It’s humbling to reveal our weaknesses to each other; however, this humble state of mind keeps the heart from many errors along the way. There’s much wisdom to gain from mature believers so that we can accomplish great tasks for the kingdom.
Read Proverbs 20:18, Colossians 1:24-29, and Hebrews 5:1-14. Who is it that you can share with and glean righteous insight from them? Ask the Lord to lead you to the right people who will help you grow in guarding your heart.
R – Refuse yourself worldly pleasures that tempt you to sin
“He chose to be mistreated along with the people of God rather than to enjoy the fleeting pleasures of sin” (Hebrews 11:25).
Moses is an example of someone who could’ve enjoyed the pleasures that Egypt offered to him. However he made the choice to turn away from temporary pleasures in order to enjoy the freedom of knowing God personally. Our hearts can be gripped to fulfill futile desires of worldliness and miss the great opportunities of experiencing God’s grace  over our lives. Our minds are easily saturated from worldly enticements offered on the Internet, TV, magazines, or books—yet we can choose to guard our hearts with purity and holiness.
Read 2 Corinthians 4:16-18, Philippians 3:17-21, and Colossians 3:2-11. What worldly vices are you tempted with? Be honest with God and yourself to turn away from anything less than holiness.
D – Develop a sensitivity to see and deal with sin in the light of Christ’s suffering because of it.
“He himself bore our sins” in his body on the cross, so that we might die to sins and live for righteousness” (1 Peter 2:24).
In this day and age, sin is dressed up with a soft, beautiful appearance. We call adultery—an affair. We call falsehood—white lies. Yet God calls it sin and will hold every person accountable. When we think about the cross with Jesus bleeding and suffering profusely because of our sins, our stomachs should turn from the stench of it. Ask the Holy Spirit to help you see your sins like God sees them.
Read Isaiah 59:1-3, Romans 6:1-14, and 1 Peter 3:18-22. How should you deal with sin knowing the incredible price that was paid for you on the cross? Spend time in prayer asking God for wisdom and strength to guard your heart from willful sins.
A true and faithful soldier is found keeping watch even everyone else is sleeping. Are you a sleeping believer? Or are you guarding your heart with due diligence? The Lord knows your strengths and weakness. It’s time to step it up in keeping holiness, purity, and faithfulness when guarding your heart.
Related Reading: 10 Idols Of Your Heart To Remove 
Resources – New International Version Bible, The Holy Bible, New International Version®, NIV® Copyright© 1973, 1978, 1984, 2011 by Biblca, Inc.™ Used by permission. All rights reserved worldwide, Holy Bible, King James Version