While there are Jews who are convinced that certain biblical commands are inscrutable and that even though we do not understand them, we must obey them, others like Maimonides and Abraham ibn Ezra were convinced that all the divine commands are rational and people can and indeed should understand them.
In his commentary to Exodus 31:18 Abraham ibn Ezra (1089-1167) put it this way. He states that foolish people wonder what Moses did on the mountain for forty days and forty nights after the revelation of the Decalogue (Ten Commandments). These foolish people think that all that God wants of them is that they act as God instructs, even if they do not understand why they should do the act.
This, he wrote, is wrong. The Torah itself insists that Jews understand the reason for the commands. Deuteronomy 30:14 states that God’s word should be “in your mouth and in your heart.” Since the ancients considered the “heart” to mean the mind, it is clear that God wants people to understand the purpose of the divine commands.
This is emphasized by the prophet Jeremiah. In 9:23, Jeremiah wrote: “Let him who glories glory in this, that he understands and knows me.”
Ibn Ezra concludes that this explains why Moses was on the mountain for forty days and forty nights; it was during this time that God explained to him the purposes of the divine commands.
 Nachmanides, for example, argued that all the biblical commands have a mystical basis and can only be understood if they are explained by a teacher of mysticism who secured his knowledge from a teacher who himself received it by tradition from sages of long ago. Rabbi Joseph B. Soloveitchik, to site another example, said repeatedly that Jews must accept the Torah teachings on “faith” and must “surrender” themselves to God. Maimonides explained all the biblical commands in book 3 of his Guide of the Perplexed. Among much else, he wrote that the biblical commands have three purposes: to teach some lessons, to help people improve, and to improve society.