{He that doeth sin} (ho poi(936e) t(886e) hamartian). "He that
keeps on doing sin" (the habit of sin). {Of the devil} (ek tou
diabolou). In spiritual parentage as Jesus said of the Pharisees
in  Joh 8:44 . When one acts like the devil he shows that he is
not a true child of God. {Sinneth from the beginning} (ap'
arch(8873) hamartanei). Linear progressive present active
indicative, "he has been sinning from the beginning" of his
career as the devil. This is his normal life and those who
imitate him become his spiritual children. {That he might
destroy} (hina lus(8869)). Purpose clause with hina and the first
aorist active subjunctive of lu(935c). This purpose (eis touto)
Jesus had and has. There is eternal conflict, with final victory
over Satan certain.