Who did sin? (ti hmarten;). Second aorist active indicative of amartanw. See Acts 3:2 ; Acts 14:8 for two examples of lameness from birth. Blindness is common in the Orient and Jesus healed many cases (cf. Mark 8:23 ; Mark 10:46 ) and mentions this fact as one of the marks of the Messiah in the message to the Baptist ( Matthew 11:5 ). This is the only example of congenital blindness healed. It is not clear that the disciples expected Jesus to heal this case. They are puzzled by the Jewish notion that sickness was a penalty for sin. The Book of Job had shown that this was not always the case and Jesus shows it also ( Luke 13:1-5 ). If this man was guilty, it was due to prenatal sin on his part, a curious notion surely. The other alternative charged it upon his parents. That is sometimes true ( Exodus 20:5 , etc.), but by no means always. The rabbinical casuists loved to split hairs on this problem. Ezekiel ( Ezekiel 18:20 ) says: "The soul that sinneth it shall die" (individual responsibility for sin committed). There is something in heredity, but not everything. That he should be born blind (ina tuplo gennhqh). Probably consecutive (or sub-final) use of ina with first aorist passive subjunctive of gennaw.