Sforno on Leviticus 19:30/ספורנו על ויקרא י״ט:ל׳

1את שבתותי תשמורו, After the Torah warned concerning a number of practices that constitute a desecration, it now proceeds to legislate days and places and people who are sacred in varying degrees. This begins with את שבתותי תשמורו, to preserve the sanctity of the Sabbath days, a sanctity bestowed on the Sabbath by G’d Himself, and including all holy convocations, מקראי קדש, whose dates have been confirmed by the Sanhedrin, the Jewish Supreme Court.

2ומקדשי תיראו, a warning to treat all holy sites with awe and reverence. This includes synagogues and all places dedicated to the service of the Lord, especially, the ones used for such activities by the public.