{They} (autoi). The heavens (ouranoi). {Shall perish}
(apolountai). Future middle of apollumi. Modern scientists no
longer postulate the eternal existence of the heavenly bodies.
{But thou continuest} (su de diameneis). This is what matters
most, the eternal existence of God's Son as Creator and Preserver
of the universe ( Joh 1:1-3  Col 1:14ff. ). {Shall wax old}
(palai(9374)h(8873)ontai). First future passive indicative of
palaio(935c), from palaios, for which see  Lu 12:33  Heb 8:13 .