The human heart expands and contracts to circulate blood through the body. When the heart contracts, it pushes blood out to the extremities. When it expands, the heart fills up with incoming blood. There’s a rare physical condition, however, that stiffens the heart muscle. This less-flexible state means that the organ can’t expand to take in the proper amount of blood—a physical hardening of the heart.

This condition can occur spiritually as well. Paul spotted it in some of the people who came to listen to him speak about Jesus. When some religious leaders came to see him, he explained that “the hope of Israel—the Messiah—[had] already come” (Acts 28:20).

They discussed this radical idea. Some believed what he said, but others didn’t. Paul quoted a passage from Isaiah that contained these words: “The hearts of these people are hardened, and their ears cannot hear, and they have closed their eyes” (Acts 28:27).

Spiritually speaking, a hard heart is an insensitive and unbelieving heart. According to Bible scholar Stan Norman, “Hardness of heart can be a refusal to hear the Word of God, or it can be a refusal to submit and obey the will of God.” So it’s possible for us to suffer deeply from the effects of our own spiritual stubbornness.

At times we may face God with arms crossed and hands balled into fists. We reject His grace and patience. But the Bible says that God’s kindness is intended to turn us from our sin (Romans 2:4). He’s the only One who can lovingly perform the “transplant surgery” we need—removing a stony, stubborn heart and replacing it with a tender, responsive heart that longs to follow Him (Ezekiel 36:26-27).

NLT 365-day reading plan passage for today: John 20:1-18