The time in both particulars is double to the former, not so much from natural causes, because the purifications in female births are longer and slower, which if it were true, yet doth not extend to any such time as here is mentioned, as for moral reasons; either to be as a blot upon that sex for being the first in man's transgression, 1 Timothy 2:14, or to put an honour upon the sacrament of circumcision, which being administered to the males, did put an end to that pollution sooner than otherwise had been; or to show the privilege of the man above the woman, and that the women were to be purified, sanctified, and saved by one of the other sex, even by the man Christ Jesus, without whom they should have still continued in their impurity.
Related Commentaries of Leviticus 12:5
Leviticus 12:5
5 But if she bear a maid child, then she shall be unclean two weeks, as in her separation: and she shall continue in the blood of her purifying threescore and six days.