What is the ruling on saying "Oh my God" out of astonishment or wonder, and not with the intention of supplication?

There is no harm in saying "Oh my God" when surprised or astonished, as long as the speaker does not intend to imitate disbelievers. Similar expressions of astonishment have been reported in Prophetic narrations and sayings of the Companions, such as "Subhan Allah (Glory be to God)" and "La ilaha illa Allah (There is no god but Allah)." However, for someone who intends to imitate disbelievers, it is forbidden for him to do so, based on the saying of the Prophet, peace and blessings be upon him: "Whoever imitates a people is one of them."