Seeing as all of Yisrael were there, what does the Torah mean when it writes "Vayikra Moshe el Kol Yisra'el"?
Oznayim la'Torah (citing the Ramban): It means that, although he had rebuked all Yisrael and designated the Arei Miklat in front of them, he called out in a loud voice, that all Yisrael should hear 1 - because now he was about to teach them Chukim and MIshpatim - the maon focus of Mishneh Torah, beginning with the Aseres ha'Dibros, just as Hashem did at Matan Torah.
See Oznayim la'Torah.
What are the implications of the double statement "ve'Limadtem osam u'Shemartem La'asosam"?
Rashi: Refer to Bechukosai, 26:3:2:1.
Yevamos, 109b: It implies that if one learns with the intention not to fulfil what one learns, there is no reward for learning. 1
Kidushin, 29a: It implies that, if a father did not teach his son Torah, he is obligated to learn it himself in order to fulfil it.
Torah Temimah: 'If theere is no fulfilment, there is no learning!'. And by the same token, it implies the opposite - ''I there is no learning, there is no fulfilment!'.