Q: Are there certain chapters of Psalms to say when praying for someone?
A: First of all, it is good to say the chapter of the person for whom you are praying, which is his age plus 1, as we learn from the Ba’al Shem Tov. For example, if a person is 23 years old, this means that he is already in his 24th year, so chapter 24 is his chapter for the year. This is the chapter that we should say when praying for him. In addition, various chapters are recommended for specific issues, and are written in some holy books and books of Psalms.
Another way to pray for someone is to spell out the letters of his name according to chapter 119 in Psalms. In this chapter, there are eight verses for every letter of the alef-beit. The correct way to spell out the name is as follows: For every letter of the person’s name, we take the verse that begins with that letter in chapter 119, as per its place in the name. For example, if we want to pray for someone named Moshe David (משה דוד) we read the first verse of the letter mem in chapter 119, followed by the second verse of the letter shin, etc. When we get to the second name, in this case, David, we continue. The letter dalet is the fourth letter, so we would read the fourth verse of the letter dalet, the fifth verse of the letter vav, etc.
If the full name has more than eight letters, we begin again from the first verse of the letter for the 9th letter of the name, etc.