In a world that constantly is being shaken how do we have an unshakable heart? In Psalm 16, David says that keeping his eyes on the Lord enabled him to have an unshakable heart.

I will praise The Lord, who counsels me; even at night my heart instructs me. I keep my eyes always on The Lord. With Him at my right hand, I will not be shaken. Therefore my heart is glad and my tongue rejoices; my body will also rest secure. – Psalm 16:7-9

In Psalm 21, David said it was his trust in God that made him unshakable:

For the king trusts in The Lord; through the unfailing love of the Most High he will not be shaken. – Ps. 21:7

David learned how to turn to God, regardless of what was happening around him, for his strength and hope. Because he fully relied on God, the giants he faced could not cause him to lose heart. In Psalm 62, it is David’s belief in God’s strength and salvation that makes his heart strong:

Truly He is my rock and my salvation; He is my fortress, I will never be shaken. – Ps. 62:2, 6

Here, David refers to God as his fortress or stronghold. 

In the Old Testament, a stronghold was a place of safety and refuge. Often, a stronghold was built on higher ground to give added protection and advantage over the enemy. In ancient warfare, the army that possessed the higher ground always had the advantage. This same principle applies to our spiritual lives. By fixing our eyes on Jesus, we cause our hearts to occupy the higher ground of the presence of God. In this way, we create a stronghold, a fortress, for ourselves against the enemy.

In the same way, when our eyes are on Jesus, our hearts will not be swayed or intimidated by the giants we face. In all circumstances, Paul’s advice holds true:

“Since, then, you have been raised up with Christ, set your hearts on things above, where Christ is, seated at the right hand of God” – Col. 3:1

When we set our hearts on Christ and His heavenly truths, the difficulties of earth will not be able to overcome us. Keeping our eyes on Him enables us to see life the way He sees it. As a result, we will have the strength of heart to respond in faith. We will have the strength of heart to live like David did. 

This is what it looks like to be imitators of Christ. He is our ultimate example of the unflinching heart of a giant slayer. Through His perseverance and strength of heart, He faced the greatest giant of all and overcame:

Let us run with perseverance the race marked out for us, fixing our eyes on Jesus, the pioneer and perfecter of faith. For the joy set before him he endured the cross, scorning its shame, and sat down at the right hand of the throne of God. Consider him who endured such opposition from sinners, so that you will not grow weary and lose heart. – Hebrews 12:1-3

His example and the grace He imparts in our lives can chase away weariness and keep us from losing heart. When we fix our eyes on Him, we become more and more like Him. And we learn to live like He lived and have a heart like His. We learn to be unshakable.