The Midrash relates that the Jews were redeemed from Egypt in the merit of four virtues. The first merit mentioned is that they didn’t change their names.

This is considered significant because all their names alluded to their ultimate redemption. Moreover, it is said that by maintaining their own language, the Jews effectively separated themselves from the Egyptians, which decreased their involvement in idolatry. The same can be said for keeping their Jewish names.

Parents receive a glimmer of divine inspiration when they give their child a Jewish name in general, the Hebrew name of every object is the conduit for its divine energy. The Arizal teaches that the same is true of every person’s name: it is the channel through which the soul’s energy reaches the body. It is said that parents receive a glimmer of divine inspiration when they give their child a Jewish name.

Naming the Baby
A baby girl is named at a Torah reading following her birth. The naming is usually accompanied by a feast to celebrate the soul’s entering the body at that time.

Rights to Name
There are various customs regarding who chooses children’s names. In some circles, the father chooses a name for the first child, the mother chooses a name for the second child, and they continue to alternate. The Lubavitcher Rebbe writes that one who has no fixed family or communal custom should follow this practice because it has its origin in ancient sources.

In any case, both parents need to agree on the name, and it should not be assigned unilaterally. The above order simply determines which spouse suggests the name for the first child, etc. However, the final decision must be mutually agreed upon.

Naming After Relatives
The Ashkenazic custom is not to name a baby after living individuals is customary to name children after deceased parents. The Ashkenazic custom is not to name a baby after living individuals. The reason for this seems to be that it is a merit for a deceased person to have a descendant (or other relative) named after him or her. If the name is given while its bearer is still alive, this will no longer be possible (in the same family) after that person’s passing.

However, if a baby was already named after a living person, its name should not be changed. But that name should not be used as the main one. This is especially so if the baby was named after another deceased relative, and the parents later realize that the name is shared by a living grandparent.

In Sephardic custom, naming children after living relatives (as well as deceased ones) is encouraged. This is considered an honor for the relative.

Different Names for Siblings
Two siblings should not share the same name. This to prevent the effect of an “evil eye” If this was mistakenly done, an additional name should be added for one of the children, which should then be used as the main name.

If a child died young, G‑d forbid, some authorities maintain that another child in the same family should not be given that same name, while others disagree.

Naming After a Wicked Person
It is forbidden to give one’s child the same name as a rasha, an evil person. This is because the verse states, “The name of the wicked should rot [and not be remembered].” In addition, bearing the same name as a wicked person may adversely affect the child’s character.

Tragic Death
In cases when a name is added, that name becomes the main nameIt is customary not to name a child after someone who passed away tragically at a young age. In such a case, the parents should change the name slightly, or add another name that will be used as the first name. In cases where the person was martyred while sanctifying G‑d’s name (e.g., in the Holocaust), it is considered a merit to give a child that name. Rabbi Moshe Feinstein writes that if the deceased passed away at a young age from a natural cause and had children, it’s possible that this rule doesn’t apply. In addition, he writes that the rule may not apply if the person was a renowned tzaddik (righteous person).

It is not necessary to follow this rule when naming after a parent or grandparent.

Changing a Name
If a name was given by a party other than the parents, the parents may choose a different name, which should be added to the name which was given.

If a person has a serious illness, it is considered a segulah (spiritually propitious act) to give him an additional name, because this name will bring him additional mazal (good fortune). The name that it added is often one that denotes healing or long life (e.g., for boys: Chaim—“life”; Rafael—the name of the angel of healing; or Alter—“elder.” For girls: Chaya—“life,” or Alta—“elder”). In cases when a name is added, that name becomes the main name. The new name is formally given at a Torah reading using the text of a mi shebeirach prayer. If possible, the person receiving the new name or a relative of that person should receive an aliyah at that time.

Being Called to the Torah by Name
When a man is called to the Torah, he is called by his Jewish name and his father’s Jewish name. In Yemenite and some Sephardic communities, the name is not called out; rather, the announcement “Ya’amod Kohen” (“Kohen, please rise”) is called out, and the man whom the gabbai had designated for this honor approaches the Torah.

When a man’s mother is Jewish but his father is a gentile, he should be called up by his maternal grandfather’s name. Some authorities say he should be called “ben Avraham,” “the son of [our Patriarch] Abraham.”

Praying For an Ill Person
When praying for someone who is ill or otherwise in need of divine assistance, we mention his or her name and mother’s (Jewish) name. Since Jewish identity is established maternally, it’s the mother that connects the soul to G‑d.

When praying for a gentile, one should mention his or her name and father’s name.

Writing a Legal Document
Correct spelling of the name is significant when writing a Jewish legal document, such as a ketubah (marriage contract) or a get (bill of divorce), the name used is the one by which the person was actually called during the preceding thirty days. Correct spelling of the name is significant, and should be established by someone familiar with Jewish law.

Name of a Prospective Spouse
Rabbi Yehudah Hechassid wrote in his testament that a man should not marry a woman whose name is the same as his mother’s, and a woman should not marry a man whose name is the same as her father’s. Some authorities say that this testament was only intended for Rabbi Yehudah Hechassid’s own descendants. Others argue that this is good advice for everyone.

The reason given is that the name in question will be used often for one’s spouse, and will not be treated with the respect owed to one’s parent.

In practice, the Tzemach Tzedek states (in the name of R. Schneur Zalman of Liadi) that one should be stringent regarding the case of a man marrying a woman whose name is the same as his mother’s, since this is also mentioned in Mishnat Chassidim, which is based on the writings of the Arizal. However, regarding the case of a woman marrying a man whose name in the same as her father’s, there is more room for leniency. In fact, the Talmud cites several examples of rabbis whose names were identical to the names of their fathers-in-law.

If one wishes to marry a man or woman who shares one’s parent’s name, an additional name may be added to the prospective spouse’s or in-law’s name, so that the names are no longer identical.​

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