Rulings of Al-Masbuq in Prayer
What are the rulings of al-masbuq who fails to join the imam in the first rak`ah (unit of prayer)?
First of all, al-masbuq is a person who attends the prayer after the imam (leader of prayer) has already offered one or more rak`ahs.
It is preferred for a Muslim to walk calmly to the mosque and make up whatever he has missed. He/she should not walk too fast or run towards the mosque in order to catch the prayer.
Abu Hurairah (may Allah be pleased with him) narrated that the Prophet (peace be upon him) said, “When you hear the Iqamah, proceed to offer the prayer with calmness and solemnity and do not make haste. And pray whatever you are able to pray and complete whatever you have missed.” (Al-Bukhari)
If a person joins that the imam while performing ruku` (bowing), he must recite the opening takbir while standing and then bow for ruku`. His prayer will not be valid if he says it while bowing. If the imam returns from ruku` before he bows, he is counted as having missed that rak`ah.
To get more information about the rulings of al-masbuq, you can watch this short video with Dr. Muhammad Salah.
Source: Huda Youtube Channel.