This is not an error of duplication. The full-fledged version of this Mitzvah are many and change for those who are learning the one/three chapter a day. The Message for the day from "Bringing Heaven Down to Earth" at the end of this Mitzvah is different than that of yesterday.

Negative Mitzvah 355: It is forbidden to take a woman as a wife without marriage
Deuteronomy 23:18 "There shall be no indecent women among the daughters of Israel"

A Jewish marriage must be held according to the law of the Torah.

This includes the entire wedding ceremony with all its details and procedures and the signing of the marriage contract.

A person is forbidden to take a woman as a wife without fulfilling these requirements.

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There is a raging storm at sea. There are hellish waves that crash and pound at the shore, carrying all away, leaving desolation behind. The sea is the world of making a living. The waves are the stress and anxiety of indecision, not knowing which way to turn, on what to rely. Up and down, hot and cold -- constantly churning back and forth. Do as Noah did and build an ark. An ark in Hebrew is "taiva" -- which means also "a word". Your ark shall be the words of Torah and of prayer. Enter into your ark, and let the waters lift you up, rather than drown you with everything else.

From: Bringing Heaven Down to Earth by Tzvi Freeman - tzvif@aol.com