Ibn ‘Abbās (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Whoever hears the prayer call and does not attend the congregational prayer, then his prayer is not valid (deficient), except if he has an excuse."
This Hadīth highlights the importance of performing prayers in congregation. The Prophet (may Allah's peace and blessings be upon him) explained that anyone who hears the call to the congregational prayer should attend it; if he does not attend, then his prayer will be incomplete and will have less reward; yet the prayer offered will be accepted, although he will be sinful for missing the congregation without an excuse. If he had a Shariah-approved excuse for missing the congregational prayer, such as sickness, rain, or fear for his life, wealth, or children, or the like, then there is no blame on him.