The Greek verb gēraskoō (γηράσκω) means to grow old or to age. It appears twice in the New Testament. In John 21:18, Jesus predicts Peter's martyrdom by saying 'when you are old.' In Hebrews 8:13, the author declares that the old covenant, by being called 'old,' 'is aging and will soon disappear.'
The most theologically significant use of gēraskoō is in Hebrews 8:13: 'By speaking of a new covenant, he has made the first one obsolete; and what is obsolete and aging will soon disappear.' The old covenant — the entire Mosaic system — was always intended to be temporary, pointing forward to Christ. Gēraskoō describes not a failure but a fulfillment: the old grew old because the new had come. The contrast between the aging old covenant and the eternal new covenant in Hebrews is one of Scripture's central theological arguments.