What should a person do when he wants to pass in front of someone praying alone in the mosque, and does this ruling apply to those praying in the Two Holy Mosques?

You have committed a great sin by speaking about Allah without knowledge, which is associated with polytheism (shirk). You must repent, seek forgiveness, and inform those who heard your initial statement that it was made without knowledge. As for passing in front of a worshipper (musalli), there are different situations:

1. Passing directly in front of the worshipper (within the place of prostration): This is forbidden and a major sin, whether the worshipper has a sutrah (barrier) or not.

2. Passing beyond the place of prostration: If the worshipper has a sutrah: It is permissible to pass behind the sutrah. If the worshipper has not taken a sutrah: It is permissible to pass beyond their place of prostration, because the prohibition specifically concerns passing directly in front of them. The most accurate opinion is that what is forbidden is passing between the worshipper's feet and their place of prostration.

This applies to an individual worshipper or an Imam. As for a congregant (ma'mum), the Imam's sutrah serves as a sutrah for those behind him. Mecca and other places are the same in this ruling due to the generality of the evidence.