The Messenger of Allah ﷺ passed by a fresh grave, so they lined up behind him and he made four takbirs over it.I asked Sha'bi, "Who narrated this to you?"He replied, "A trustworthy person who witnessed it, Abdullah bin Abbas."
حدثنا محمد بن العلاء قال أخبرنا ابن إدريس قال سمعت أبا إسحق
أن رسول الله ﷺ مر بقبر رطب فصفوا عليه وكبر عليه أربعا فقلت للشعبي من حدثك قال الثقة من شهده عبد الله بن عباس
Recorded by Muslim in the chapter on funerals, section on the funeral prayer over the grave, hadith no. 954, from the hadith of Abdullah bin Idris, and by Bukhari in the chapter on funerals, section on announcing the funeral, hadith no. 1247, from the hadith of Abu Ishaq, through the same chain.