Hebrews 6:18 Immutable .. unchangeable; 1) the Promise, v. 13; 2) the oath, v. 16, that confirmed it. Fled for refuge .. [Three metaphors] 1) metaphor of cities of Refuge. Exodus 21:14, Numbers 3:25 ff, Deuteronomy 4:42; Deuteronomy 19:5; Joshua 20:8. 2) v. 19 metaphor - storm tossed sailors at sea. 3) v. 20 travelers preceeded by forerunner.