New Defender's Study Bible Notes
15:26 The last enemy. The last enemy to be destroyed will be the first enemy who rebelled against God in the beginning and who has been deceiving the world with his lies ever since. Satan, who now has “the power of death” (Hebrews 2:14) will finally be incarcerated forever in the lake of fire (Revelation 20:10).
15:54 saying that is written. See Isaiah 25:8, supplemented by Hosea 13:14. In I Corinthians 15:55, “death” and “grave” are the same Greek word, thanatos.