Moses wrote all the words of the Lord. We may presume that they were miraculously brought to his remembrance by that Spirit of Truth which guided all the Prophets (2 Peter 1:21; John 14:26). Having written the words, he waited till the next day, and then rose up early and builded an altar, in preparation for the sacrifice without which no covenant was regarded as binding.
And twelve pillars. Symbolical of the twelve tribes. Compare Joshua 4:3, Joshua 4:9, Joshua 4:20.