I saw the Prophet ﷺ and Abu Bakr and Umar walking before the funeral.  

رَأَيْتُ النَّبِيَّ ﷺ وَأَبَا بَكْرٍ وَعُمَرَ يَمْشُونَ أَمَامَ الْجَنَازَةِ  

(I think that the people of Ziyad informed me that he reported on the authority of the Prophet ﷺ: A rider should go behind the bier, and those on foot should walk behind it, in front of it, on its right and on its left keeping near it. Prayer should be offered over an abortion and forgiveness and mercy supplicated for its parents.  

أَنَّهُ رَفَعَهُ إِلَى النَّبِيِّ ﷺ قَالَ الرَّاكِبُ يَسِيرُ خَلْفَ الْجَنَازَةِ وَالْمَاشِي يَمْشِي خَلْفَهَا وَأَمَامَهَا وَعَنْ يَمِينِهَا وَعَنْ يَسَارِهَا قَرِيبًا مِنْهَا وَالسِّقْطُ يُصَلَّى عَلَيْهِ وَيُدْعَى لِوَالِدَيْهِ بِالْمَغْفِرَةِ وَالرَّحْمَةِ