σκληρύνω
to indurate, i.e. (figuratively) render stubborn
Everything you need to know.
of Completion
This certifies that
Is on track to complete the Bible for the 1st time in 240 days.
Paul's Handkerchief is Bible study with a difference — going word-by-word through Scripture to reclaim the Ancient Near East context, romance, and mystery that modern translations often leave behind.
Only about 3% of people around the world who start the Bible ever finish it. The 3% Club is for those ready to break that cycle — reading the entire Bible at their own pace, backed by community and tools built to make finishing not just possible, but inevitable. You also get a certificate to celebrate your achievement.
Bible Cafe isn't just Bible study — it's a personal, intimate conversation with Him. Think less classroom, more kitchen table. It combines the original Coffee with Jesus experience with activities like quizzes, crosswords, journaling and more, all designed to let the Word shape your heart, not just your head.
Most English Bibles can't carry the full weight of what's in the original Hebrew and Greek. The F.O.G Bible Project exists to change that — three new translations built publicly (a Study Bible, a Reader's Bible, and F.O.G Jr. for younger readers), plus a word-by-word renewal of Strong's Concordance restoring the depths most translations leave behind. It is Jean Paul's lifelong work, unfolding in public — and you're invited in.
Jean Paul Joseph is the lead editor of the F.O.G Bible Project. He works from a personal encounter with Jesus first, then draws on the scholarship of respected Jewish and Christian scholars — because the church was Jewish before it was anything else, and those roots change everything about how you read Scripture.
Simply create an account and choose your preferred Bible and reading style. The app will track your progress and help keep you accountable to the rhythm of daily Scripture engagement.
to indurate, i.e. (figuratively) render stubborn
σκληρύνω(sklērýnō)
Strong’s Definition
to indurate, i.e. (figuratively) render stubborn
from G4642 (σκληρός);
“But when divers were hardened, and believed not, but spake evil of that way before the multitude, he departed from them, and separated the disciples, disputing daily in the school of one Tyrannus.”
No verses found containing this word study ID.
The Stone That Refuses the Rain
Six times this verb appears in the sacred pages, yet each occurrence carries the weight of a world unmade. Σκληρύνω — sklērýnō — is not merely a word about resistance; it is the sound of a heart turning to flint against the living God. You must understand this from the beginning: this is not a passive condition but an action, a verb that moves, that chooses, that hardens what was once soft. The first time the New Testament speaks this word, it is on the lips of the apostle Mark, describing the disciples themselves: their hearts were hardened (Mark 6:52). Even those who walked with Yeshua could become stone.
The Grammar of a Closed Door
Consider the tense and voice of this verb, for the grammarians among you will see the soul of the matter. In the New Testament, sklērýnō appears most often in the aorist passive — a completed action, a state entered into. The passive voice is crucial here: the heart does not harden itself alone, but is hardened. Yet who performs the action? In the letter to the Hebrews, the voice shifts: "Today, if you hear his voice, do not harden your hearts" (Hebrews 3:8). Here the verb is in the aorist active subjunctive — a command, a warning, a choice. The ancient sages observed that the human will is like clay in the potter's hands, but clay can refuse the wheel. The Greek philosophical tradition spoke of stereotes, firmness of character, as a virtue. But the apostolic writers turned this virtue on its head: what is firmness toward God is hardness against Him.
The Bridge of the Septuagint
When the Seventy translators rendered the Hebrew Scriptures into Greek, they chose sklērýnō to carry a weighty Hebrew counterpart: qashah (קשה), meaning to be hard, severe, or stubborn. In Exodus 7:3, the Lord says, "I will harden Pharaoh's heart." The LXX uses sklērýnō there, and this single translation choice reveals the great mystery of divine sovereignty and human responsibility. Pharaoh's heart was not made of stone by God alone — the Hebrew text shows Pharaoh hardening his own heart first (Exodus 8:15), and then God confirmed what Pharaoh had chosen. The rabbis of old taught that God sends judgment only after a man has chosen his own path. The Greek word thus bridges two worlds: the Hebrew understanding of a heart that becomes heavy (kaved) and the Greek concept of a will that becomes inflexible.
The Parable of the Sower and the Path
Yeshua himself wove this verb into the fabric of his most famous teaching. In the parable of the sower, the seed that falls along the path is trampled, and the birds devour it. But Mark's Gospel adds a chilling detail: those who are "outside" see but do not perceive, lest they should turn and be forgiven — "lest they should turn again, and it should be forgiven them" (Mark 4:12). The quotation is from Isaiah, and the early church understood that a hardened heart is the judgment upon those who have seen the light and refused it. The apostolic tradition teaches that Yeshua spoke in parables not to obscure truth, but to let the sklērýnō of the heart reveal itself. The same sun that melts wax hardens clay.
Send a Gift
This website is 100% donor-funded. Your generosity allows someone else to access this content for free.
Give a gift of $100 to sponsor a verse or page of your choice.
Paul's Theology of the Stone
The apostle Paul, that master of the inner life, takes up this verb and makes it the center of his most agonizing reflection. In Romans 9:18, he writes, "So then He has mercy on whom He wills, and He hardens whom He wills." You must sit with this verse as a man sits with a wound. Paul is not giving you a system; he is giving you a mystery. The sklērýnō of God is not cruelty but consequence — the same divine presence that softens the repentant heart into tears becomes a fire that bakes the rebellious heart into stone. The early church father Ignatius wrote that God's hardening is like a physician who allows a wound to close improperly when the patient refuses treatment. Paul uses this verb more than any other New Testament writer, and he does so to show that the gospel is both a fragrance of life and a smell of death (2 Corinthians 2:16).
The LXX Depth: From Pharaoh to the Prophets
Beyond Exodus, the Septuagint uses sklērýnō to translate the Hebrew hizziq (חזק) — to strengthen, to make firm. In Deuteronomy 2:30, Sihon king of Heshbon would not let Israel pass because the Lord had hardened his spirit. Here the Greek word takes on a dimension of divine purpose: the hardening of a king serves the redemption of a people. The prophet Zechariah speaks of those who made their hearts like flint (Zechariah 7:12), and the LXX renders this with sklērýnō. The Hebrew word behind it, shamayim as flint, evokes the hardness of a diamond. Jewish tradition holds that the prophet's message was rejected not because it was unclear, but because the people had polished their hearts into mirrors that reflected only themselves. Every use of sklērýnō in the LXX echoes this: the word is not about a passive state but an active refusal, a strengthening of the will against the voice of God.
Yeshua, the Heart That Did Not Break
Now come to the Messianic fulfillment, for here is the great reversal. The New Testament writers never apply sklērýnō to Yeshua — not once. His heart was not hardened, though he faced every temptation that would turn a man to stone. When the Pharisees hardened their hearts and watched to see if he would heal on the Sabbath, Yeshua looked at them with anger, grieved at the hardness of their hearts (Mark 3:5). The word there is the noun form, sklērokardia, but the root is the same. He did not become like them. Instead, he took upon himself the full weight of human sklērýnō — the rejection, the flint-like refusal of his own people — and let it break him on the cross. The apostolic faith proclaims that where the first Adam hardened his heart in the garden, the second Adam opened his heart on Golgotha. The stone that the builders rejected became the cornerstone (Psalm 118:22).
Your Heart, This Day
And so I speak to you directly, beloved reader. You have heard the word of the Lord today. Do not let it fall upon the path of your heart like seed upon a road beaten hard by the traffic of your own will. The verb sklērýnō is not a verdict upon you from afar; it is a choice you make with every refusal, every distraction, every small rebellion you call private. The rabbis of old said that the evil inclination is like a stone — the more you polish it, the more it shines, but it remains stone. Only the living waters of the Spirit can make a heart of flesh where there was a heart of stone. Today, if you hear his voice, do not harden your heart. Let the rain of his mercy find the soil of your soul soft and ready. For the One who was broken for you stands at the door of your inner temple, and he will not force the lock. He only knocks.