Mibrach (מִבְרָח) designates a person who has fled — a fugitive, an escapee. It comes from barach (H1272, to flee, to run away). The word appears in Isaiah's oracle against Egypt, describing those who would seek refuge there and find none.
Flight and refuge are recurring motifs in Scripture. Moses fled Egypt (Exod. 2:15). Elijah fled Jezebel (1 Kings 19). David fled Saul across the wilderness. The mibrach is not cowardly but desperate — and Scripture consistently shows God meeting people in their flight. Cities of refuge (are miklat) were specifically designated for the unintentional manslayer — institutionalized mercy for the mibrach. The ultimate refuge is not a city but a Person: "God is our refuge" (Psalm 46:1). In Isaiah's taunt, those fleeing to Egypt find a false refuge — the contrast pointing to the true refuge in YHWH.
The root barach (H1272) covers both panicked flight and strategic retreat. Jacob barach from Esau (Gen. 35:7) — years later, God met him at Peniel in that same flight. Jonah barach from God — and found there is no flight outside God's reach. Hebrews 6:18 transforms the fugitive image theologically: believers themselves are ones who have "fled" — to Christ — and found the anchor-hold of hope.