We are taught in Dubbieland that this means....
*** it-1 pp. 616-617 Destruction ***
The possibility of eternal destruction for some is also indicated by Jesus’ words at Matthew 10:28: “Do not become fearful of those who kill the body but cannot kill the soul; but rather be in fear of him that can destroy both soul and body in Gehenna.” Regarding this text, The New International Dictionary of New Testament Theology (edited by C. Brown, 1978, Vol. 3, p. 304) states: “Matt. 10:28 teaches not the potential immortality of the soul but the irreversibility of divine judgment on the unrepentant.” Also, Bauer’s Greek-English Lexicon of the New Testament (revised by F. W. Gingrich and F. Danker, 1979, p. 95) gives the meaning “eternal death” with reference to the Greek phrase in Matthew 10:28 translated “destroy both soul and body in Gehenna.” Thus, being consigned to Gehenna refers to utter destruction from which no resurrection is possible.—See GEHENNA.
Besides if you love Jehovah ......you don't simply obey because of potential rewards or punishment.