What is the second commandment that Moses recalls?
Leviticus 26:2 (ESV)
2You shall keep my Sabbaths and reverence my sanctuary: I am the LORD.
Leviticus 26:2 is an exact duplication of Leviticus 19:30. It is a restatement of the Fourth Commandment. This repetition highlights the absolute centrality of the Sabbath and the importance of holiness within the sanctuary.
2 You shall keep my Sabbaths and reverence my sanctuary: I am the LORD.