{Doeth no sin} (hamartian ou poiei). Linear present active
indicative as in verse  4  like hamartanei in verse  8 . The
child of God does not have the habit of sin. {His seed} (sperma
autou). God's seed, "the divine principle of life" (Vincent).
Cf.  Joh 1 . {And he cannot sin} (kai ou dunatai hamartanein).
This is a wrong translation, for this English naturally means
"and he cannot commit sin" as if it were kai ou dunatai
hamartein or hamart(8873)ai (second aorist or first aorist active
infinitive). The present active infinitive hamartanein can only
mean "and he cannot go on sinning," as is true of hamartanei in
verse  8  and hamartan(936e) in verse  6 . For the aorist
subjunctive to commit a sin see hamart(8874)e and hamart(8869) in
 2:1 . A great deal of false theology has grown out of a
misunderstanding of the tense of hamartanein here. Paul has
precisely John's idea in  Ro 6:1  epimen(936d)en t(8869) hamarti(8369)
(shall we continue in sin, present active linear subjunctive) in
contrast with hamart(8873)(936d)en in  Ro 6:15  (shall we commit a sin,
first aorist active subjunctive).