What is the legal ruling on some worshipers preferring to pray in the outdoor courtyards of the mosque instead of inside it, despite the availability of vacant spaces?

Congregants should not pray outside the mosque when there is space available inside, as this leads to missing the completion of rows and contradicts the guidance of the Prophet (PBUH) and his companions. As for the validity of the prayer, if those in the courtyard can see the congregants inside the mosque, their prayer is valid. However, if they cannot see them, the validity of following the Imam is a matter of scholarly disagreement. The preponderant opinion is that it is valid if one can hear the Imam's voice or the voice of someone who can hear him.