Placing notes in the Western Wall refers to the practice of placing slips of paper containing written prayers to God into the cracks of the Western Wall, a Jewish holy site in the Old City of Jerusalem.
It is claimed that occurrence of such a phenomenon dates from the early 18th century and stems from the Jewish tradition that the Divine Presence rests upon the Western Wall. There is however a dispute as to whether it is permissible according to Jewish law to insert slips of paper in to the crevices.[1] Some argue that the practice debases the holiness of the Wall and that the placement of notes should be discontinued.[1]
A practical issue in connection with the kotel ha'maravi is whether it is permitted to insert one's fingers or notes into the crevices of the wall" and "Others have argued that since this pollutes the kotel, and there is no halachic reasoning for this practice, that it is not proper to allow it to continue.