Jamieson, Fausset and Brown on Ephesians 4:22

22. That ye--following "Ye have been taught" (Ep 4:21).

concerning the former conversation--"in respect to your former way of life."

the old man--your old unconverted nature (Ro 6:6).

is corrupt according to the deceitful lusts--rather, "which is being corrupted ('perisheth,' compare Ga 6:8, 'corruption,' that is, destruction) according to (that is, as might be expected from) the lusts of deceit." Deceit is personified; lusts are its servants and tools. In contrast to "the holiness of the truth," Ep 4:24, and "truth in Jesus," Ep 4:21; and answering to Gentile "vanity," Ep 4:17. Corruption and destruction are inseparably associated together. The man's old-nature-lusts are his own executioners, fitting him more and more for eternal corruption and death.