Greek splagchnizomai (σπλαγχνίζομαι) — "to be moved with compassion, to be gut-wrenched with pity." Derived from splagchna — the inward parts: bowels, heart, liver. In Greek thought (and Hebrew racham / rechem, "womb-compassion"), the deepest emotions were located in the viscera, not the head. The verb is strong: it does not mean mild sympathy but a physical, gut-level churning at the sight of suffering. In the NT it is used almost exclusively of Jesus — twelve times — and in three parables of His (the prodigal's father, the good Samaritan, the merciful king).
Splagchnizomai is the pulse of Jesus' ministry. He sees the crowds "harassed and helpless, like sheep without a shepherd" and is gut-wrenched (Matthew 9:36). He sees the leper and is gut-wrenched (Mark 1:41). He sees the widow burying her only son at Nain and is gut-wrenched, touches the bier, and raises the boy (Luke 7:13-15). He sees the hungry crowd after a long day of teaching and is gut-wrenched (Mark 8:2). In the parable of the Good Samaritan, the Samaritan is moved with the same verb (Luke 10:33); in the Prodigal Son, the father sees his son "while he was yet a long way off" and is splagchnizomai-ed (Luke 15:20). This is the heart of God toward sinners. Modern Christians sometimes present Christ as the stoic, dispassionate teacher — the Greeks' philosophical ideal — or as an angry prophet only. The Gospels present Him as the One whose gut churns with compassion at the sight of human suffering. We do not have a High Priest who cannot sympathize (Heb 4:15). When your gut hurts for another human being, you are experiencing a small shadow of the heart of Christ. That feeling is trustworthy — act on it.