Among the earliest prayers recorded are those for the sick. Moses prayed for his leprous sister, Miriam: "Heal her now, O God, I beseech Thee" (Num. 12:13). When Hezekiah was gravely ill, he "turned his face to the wall and prayed unto the Lord" (Isa. 38:2). A benediction for the healing of the sick was incorporated as the eighth blessing in the daily Amidah. Those who visit the sick pray for their recovery (Rema to Sh. Ar., YD 335:4). In the Middle Ages the custom arose of invoking a blessing for the sick, known as the *Mi she-Berakh, during the reading of the Torah. The person requesting the recitation of the prayer for a relative or friend usually pledges charity. On the Sabbath the prayer concludes as follows: "It is the Sabbath, when one must not cry out, and recovery will soon come" (Shab. 12a). The name of a gravely ill person is often changed during this prayer in accordance with the statement of the rabbis that a change of name cancels one's doom (RH 16b; Sefer Ḥasidim, ed. by R. Margalioth (1957), 213, nos. 244, 245, ed. by Wistinetzki, par. 365; see *Name, Change of).
Psalms are also read for a gravely ill person in the following order (according to one tradition): 90–108, 20, 38, 41, 86, 118. Those verses in Psalm 119 which begin with the letters of the sick person's name are then read. The recitation is concluded with the verses in the same psalm whose initial letters spell קְרַ״ע שָׂטָן (kera Satan; "Destroy Satan").
H.M. Rabinowicz, A Guide to Life (1964), 12f.; J.M. Tukacinsky, Gesher ha-Ḥayyim, 1 (19602), 30ff.