***There is a new covenant in place, and with the new covenant there are new obligations for one who wishes to become a child of God.***
Mat 11:12 And from the days of John the Baptist until now the kingdom of heaven suffereth violence, and the violent take it by force.
Mat 11:13 For all the prophets and the law prophesied until John.
Luk 16:16 The law and the prophets [were] until John: since that time the KINGDOM OF GOD is preached, and every man presseth into it.
The new covenant I am referring to is the convenant that was put in place upon the death, burial, and resurrection of Christ. The time in which John's baptism was in effect ended once the new covenant became effective.