Introduction
One verse after the famous 'the heart is deceitful' (v. 9), Jeremiah names the One who can know it: the Lord Himself. Verse 9's diagnosis is answered by v. 10's Diagnostician — only God sees the heart we cannot.
Historical Context
Judah's leaders were assuring themselves of God's favour while pursuing idols. Jeremiah delivers a two-verse pairing: human hearts are unknowable to themselves (v. 9), but fully known to God (v. 10) — who judges by the ways those hearts produce.
Original Language Insights
'Reins' (kelayot) — kidneys, the seat of deepest affections in Hebrew anthropology.
'Search' (choqer) — to investigate thoroughly.
'Fruit' (peri) — God reads the heart by the actions it produces.
Theological Significance
Self-knowledge is limited; divine knowledge is total. Where v. 9 humbles us about our own heart, v. 10 directs us to the only Heart-Reader. Final judgment is fair because the Judge knows what no one else can know.
Practical Application
Pray Psalm 139:23-24 alongside Jer 17:10 — invite the Lord to search what you cannot. And live now in light of the certainty that He already knows; nothing will be hidden at the end.