Musar su Esodo 20:1

If at Sinai it says וידבר אלוקים to indicate that the attribute of Justice was being applied to certain types of people, the word ואלה is a continuation of that thought as applied to the judges of the Jewish people.

וידבר אלהים את כל הדברים האלה לאמר. The word לאמר, suggests that G–d rehearsed the words he was going to say to Israel before actually saying them. We must surely learn from here that an ordinary mortal must carefully review what he is going to say before saying it, if even G–d is reported as doing so.

I have found the following comment by Nachmanides on the commandment לא תשא את שם ה' אלוקיך לשוא: "They heard the first two commandments from G–d directly. This is why the sages said that these two commandments are the essence of all the Commandments. How do we reconcile this with the view of Rabbi Eliezer who points out that the Torah says in Exodus 20,1: 'G–d spoke all these words?' Moses said to the people in Deut. 5,19: את הדברים האלה דבר ה' אל כל קהלכם בהר מתוך האש. 'G–d spoke these words to your entire congregation at the Mountain out of the fire.' The Torah (Moses) continues there: 'He inscribed them on two stone tablets and gave them to me' (Moses). This clearly implies that what G–d inscribed on the tablets was exactly what He had said to the people!