Are there any Hadith from the Prophet, may Allah bless him and grant him peace, that encourage holding feasts for specific occasions such as marriage and circumcision?

The wedding feast (Walimat al-Urs) is a confirmed Sunnah (definition) or obligatory. As for the circumcision feast (Walimat al-Khitan (definition)), it is permissible; some scholars disliked it, while others recommended it. Similarly, the childbirth feast (Walimat al-Wiladah) is permissible. The 'Aqiqah (definition) is a Sunnah, and scholars differed on whether people should be invited to it or if its meat should be given as charity and shared with neighbors and friends. The Hanbali school of thought holds that there is no harm in inviting people to it.