Jamieson, Fausset and Brown on Hebrews 1:12

12. vesture--Greek, "an enwrapping cloak."

fold them up--So the Septuagint, Psa 102:26; but the Hebrew, "change them." The Spirit, by Paul, treats the Hebrew of the Old Testament, with independence of handling, presenting the divine truth in various aspects; sometimes as here sanctioning the Septuagint (compare Is 34:4; Re 6:14); sometimes the Hebrew; sometimes varying from both.

changed--as one lays aside a garment to put on another.

thou art the same--(Is 46:4; Mal 3:6). The same in nature, therefore in covenant faithfulness to Thy people.

shall not fail--Hebrew, "shall not end." Israel, in the Babylonian captivity, in the hundred second Psalm, casts her hopes of deliverance on Messiah, the unchanging covenant God of Israel.