A mikveh or Mikvah (Hebrew: מִקְוֶה / מקווה, Modern: mīqve, Tiberian: mīqwe, pl. mikva'ot, mikvot, or (Ashkenazic) mikves[1][2] lit., "a collection") is a bath used for ritual immersion in Judaism[3] to achieve ritual purity.
mikveh has its counterpart in Christianity, called baptism, though Christian baptism is one of the main requirements for conversion to Christianity, while the Jewish mikveh focuses mainly on ritual purity.[
• Baptism, Ghusl, Misogi, Masbuta, Tamasha – similar rituals in other religions
The traditional rules regarding the construction of a mikveh are based on those specified in classical rabbinic literature. Numerous biblical laws indicate that one must "bathe their flesh in water" to become purified from ritual impurity.[21] The type of bathing is specified in Leviticus 11:36, which states that "a spring, or a cistern, a gathering (mikveh) of water" is a source of purity. A mikveh must be built into the ground or built as an essential part of a building. Portable receptacles, bathtubs, whirlpools, or jacuzzis cannot therefore function as mikvot.
Mikveh water must have collected naturally (bidei shamayim) rather than by human action. Thus, mikveh water must flow naturally to the mikveh from the source (rain or a spring).[25] This essentially means that it must be supplied by gravity or a natural pressure gradient and cannot be pumped there by hand or carried.
The word mikveh makes use of the same root letters in Hebrew as the word for "hope", and this has served as the basis for homiletical comparison of the two concepts in both biblical and rabbinic literature. For instance, in the Book of Jeremiah, the word mikveh is used in the sense of "hope", but at the same time also associated with "living water":
O Hashem, the Hope [mikveh] of Israel, all who forsake you will be ashamed... because they have forsaken Hashem, the fountain of living water[68]
Are there any of the worthless idols of the nations, that can cause rain? or can the heavens give showers? Is it not you, Hashem our God, and do we not hope [nekaveh] in you? For you have made all these things.