Jabir bin 'Abdullah said that:
We were with the Prophet ﷺ, and he drew a line (in the sand), then he drew two lines to its right and two to its left. Then he put his hand on the middle line and said : 'This is the path of Allah. Then he recited the Verse: And verily, this (i.e. Allah's Commandments) is My straight path, so follow it and follow not (other) paths, for they will separate you from His path..."

حَدَّثَنَا أَبُو سَعِيدٍ عَبْدُ اللَّهِ بْنُ سَعِيدٍ، حَدَّثَنَا أَبُو خَالِدٍ الأَحْمَرُ، قَالَ سَمِعْتُ مُجَالِدًا، يَذْكُرُ عَنِ الشَّعْبِيِّ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ، قَالَ كُنَّا عِنْدَ النَّبِيِّ ﷺ فَخَطَّ خَطًّا وَخَطَّ خَطَّيْنِ عَنْ يَمِينِهِ وَخَطَّ خَطَّيْنِ عَنْ يَسَارِهِ ثُمَّ وَضَعَ يَدَهُ فِي الْخَطِّ الأَوْسَطِ فَقَالَ " هَذَا سَبِيلُ اللَّهِ " . ثُمَّ تَلاَ هَذِهِ الآيَةَ {وَأَنَّ هَذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ وَلاَ تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَنْ سَبِيلِهِ} .