Is there a mitzvah to daven for the health of others?

During the brocha of Refoeinu, a person may add a special supplication on behalf of a specific person who is sick. If the sick person is in front of him, the one who is davening does not need to specify his name. Otherwise, he should say his name and the name of his mother. The poskim say that one should not add this supplication every time he davens; otherwise, it seems as if he is making the supplication a permanent part of the brocha. When one davens on behalf of people who do not live in his household, he also fulfills the mitzvah of v’ahavta l’rayacha komocha. If he wishes to daven on behalf of two sick people--one who lives in his house and who does not--he should first mention the one who does not live in the house. In the merit of davening for others, he will receive his own salvation first. 

סי' קי"ז ס"א ס"ק ג' ביאורים ומוספים דרשו 1, 2

How should a mother daven for a child who is ill?

The following halachos apply to davening for people who are ill: 1) There should not be large gatherings to daven on behalf of people who are terminally ill. If the tefillos are not fulfilled, there may be a weakening in some people’s emunah. 2) Some Rishonim say that if a person is very ill and suffering tremendously, people should daven that he should die to alleviate his suffering. Contemporary poskim say that this concept cannot be applied practically, since we are not experts in determining when a person reaches such a state. If the doctors say that there is no hope, one may stop davening for the healing of the choleh. 3) If one does not know the patient’s mother’s name, he may say his father’s name instead. If this is not an option, he may use his last name or another descriptive term. 4) A mother who is davening on behalf of her child should say “my son/daughter”.

ביאורים ומוספים דרשו 1, 2, 3

When should a visitor to Eretz Yisroel begin saying V’Sein Tal Umatar?

In Eretz Yisroel, one begins saying V’sein Tal Umatar on the seventh of Cheshvan. In Chutz L’Aretz, the proper time is sixty days after the onset of the tekufah (which falls on December fourth or fifth, depending on whether it is a leap year in the Gregorian calendar). If a resident of Eretz Yisroel is visiting Chutz L’Aretz during the time when they have not yet begun to say V’sein Tal U’matar, the Achronim disagree as to what he should say. A similar question arises when a resident of Chutz L’Aretz visits Eretz Yisroel. Practically, some contemporary poskim give the following rulings: 1) If an Israeli arrived in Chutz L’Aretz before he started saying it, he should begin saying it on Zayin Cheshvan but only add it during the brocha of Shema Koleinu. If he already started saying it before he arrived, he may continue saying it in its proper place. 2) If he plans to stay in Chutz L’Aretz, he should adhere to the local custom. 3) If a resident of Chutz L’Aretz is visiting Eretz Yisroel and plans to return before December fourth, he should only add it in Shema Koleinu. If he is staying past that point, he may insert it in its proper place.

סי' קי"ז ס"א ס"ק ה' ביאורים ומוספים דרשו 9

• If one does ninety practice runs of the brocha with the correct addition, the Rishonim disagree about whether he can then be established as fluent in the text.

• Rema rules that ninety practice runs can be used both in the summer and winter. In the winter, one should begin with the words mechaye meisim Atah and continue with mashiv haruach. In the summer, one should begin at the same point, omit mashiv haruach, and finish with the words mechalkel chaim. Others disagree with this last point and hold that one cannot practice by omitting words.

• During the brocha of Selach Lonu, a person should think about specific sins that he may have done and make up his mind to rectify them. There is a custom to hit one’s heart with his fist. This is a symbolic gesture of chastising the heart for causing the sin. 

• May one say V’Sein Tal Umatar in the summer?

• Is necessary to go back if one said V’sein Tal Umatar too early?

• When is V’sein Tal Umatar said in the Southern Hemisphere?