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A ba'al teshuvah' (Hebrew: בעל תשובה; for a woman, בעלת תשובה, baalat teshuva or baalas teshuva; plural, בעלי תשובה, baalei teshuva, "master of return [to God]"). Baal teshuvah literally means in Hebrew "master of return" i.e., one who has "returned" to God.
The Zohar’s comment is difficult to understand, since snakes and scorpions are more likely to harm a person! This teaching can be explained as follows: There are two types of suffering. The first type — symbolized by the snakes and scorpions — is suffering sent by Heaven. Though it is hard to endure, a person can look beyond this type of suffering and come to recognize God’s message and His Kindness that transcend the suffering. The second type is that caused by human beings. When a person suffers due to human beings, it is harder to look beyond the suffering, because his enemies are bent on deflecting him from thinking about God altogether. Thus, suffering caused by human beings is far greater than suffering sent directly from God 
Originally, the term referred to a Jew who transgressed the halakhah (Jewish law) knowingly or unknowingly and completed a process of introspection to "return" to the full observance of God's mitzvot. According to the Talmud, a true "ba'al teshuvah" stands higher in shamayim (lit. "heaven") than a "frum from birth", even higher than a tzadik, chasal says. In contemporary times, the phrase is primarily used to refer to a Jew from a secular background who becomes religiously observant (normally in an Orthodox fashion) later in life. The alternative term, chozer b'teshuvah (חוזר בתשובה) is more commonly used in Israel.