Deuteronomy 9:10

With the finger of God Immediately and miraculously, which was done not only to procure the greater reverence to the law, but also to signify that it is the work of God alone to write this law upon the table of men's hearts. In the day of the assembly That is, when the people were gathered by God's command to the bottom of mount Sinai, to hear and receive God's ten commandments from his own mouth.