The Three Covenants

דברים א ,א: לֶּא הֶּ שֹמ רֶּּבִּד רֶּ שֲא םיִרָבְּׁדַה הֶּ לֵּא -כָּל-יִש ְׁרָ אֵּל
Baal HaTurim comments that 'Devarim', 'ha'devarim', 'eileh ha'devarim' is a hint to the three times that the Mitzvos were said, at Sinai, in the Ohel Mo'ed and in Arvos Mo'av. On each and every Mitzvah, he adds, He made sixteen covenants, a total of forty-eight all in all. Corresponding to this, the Torah warns against Avodah-Zarah forty-eight times, and likewise it issues forty-eight warnings against abusing a Ger, who comes to cleave to the Torah, on which forty-eight covenants were made.