مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2314
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه) that The Prophet (ﷺ) used to deliver the khutbah on Friday standing, then he would sit down, then he would stand up and deliver (the second) khutbah.
Musnad Ahmad 2322Hasan]