Despite declaring repentance, he was deported back to Saudi Arabia and was taken into police custody to face a trial.
Tension has risen in recent years between religious conservatives and reformers over the pace of gradual political, economic and social reforms in a country with a large young population.
Saudi analyst Jamal Khashoggi said the law required extensive public debate.
"I would rather have this law discussed by the public first. It should not only be debated by the Shura, it should be debated in newspapers first because it can be misused," Khashoggi said.
"I don't want anything to affect my freedom and we don't want Saudi Arabia to be another Iran."
(Reporting by Asma Alsharif)