From an unused root; moschos refers to a calf, young bull, or young animal. Used in Hebrews for sacrificial animals, in Revelation for the face of the second living creature, and poignantly in Luke 15:23 — the fatted calf slaughtered to celebrate the prodigal son's return.
The moschos — the fatted calf — in Luke 15:23 is one of the most theologically loaded images in all the parables of Jesus. The father commands: 'Bring the fattened calf and kill it. Let us eat and celebrate.' This is the language of sacrifice and feast. In the OT, a calf sacrifice was reserved for the most significant occasions — covenant ratifications (Gen. 18:7 — Abraham for his heavenly guests), great celebrations, and priestly installations. The father's command to kill the fatted calf for a returning sinner is a covenantal welcome home — not just a meal but a declaration: 'This son of mine was dead and is alive again; he was lost and is found' (Luke 15:24). The elder brother's anger at the feast reveals the Pharisee's heart — unwilling to join the covenantal celebration of sinners restored. In Hebrews 9:12, 19, the calf's blood represented the old covenant's sacrificial system — now superseded by 'the precious blood of Christ, a lamb without blemish or defect' (1 Pet. 1:19).