G0276–ἀμετάθετος–ametathetos

in which God, more abundantly willing to shew to the heirs of the promise the immutability of his counsel, did interpose by an oath,

ἀμετάθετον ametatheton “unchangeableness”

that through two immutable things, in which `it is' impossible for God to lie, a strong comfort we may have who did flee for refuge to lay hold on the hope set before `us',

ἀμεταθέτων, ametathetōn “unchangeable,”