ENOfficial
Jabir said God’s messenger forbade that graves should be plastered with gypsum, have any writing on them, or be trodden on. Tirmidhi transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ جَابِرٍ قَالَ: نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَن تجصص الْقُبُور وَأَن يكْتب لعيها وَأَن تُوطأ. رَوَاهُ التِّرْمِذِيّ
sunnah.com