Waiting for four months is ordained for those who take an oath for abstention from their wives. The waiting period of the woman whose husband dies is four months and ten days. When Abraham said: "My Lord, show me how You give life to the dead," Allah said: "Why! Do you have no faith?" Abraham replied: "Yes, but in order that my heart be at rest." He said: "Then take four birds, and tame them to yourself, then put a part of them on every hill, and summon them; they will come to you flying. [Al-Baqara 2:260]
The respite of four months was granted to give time to the mushriks in Surah At-Tawba so that they should consider their position carefully and decide whether to make preparation for war or to emigrate from the country or to accept Islam. Those who accuse honorable women (of unchastity) but do not produce four witnesses, flog them with eighty lashes, and do not admit their testimony ever after. They are indeed transgressors. [An-Noor 24:4]

Taoism
Four Symbols of I Ching

Other
In a more general sense, numerous mythological and cosmogonical systems consider Four corners of the world as essentially corresponding to the four points of the compass. Four is the sacred number of the Zia, an indigenous tribe located in the U.S. state of New Mexico. The Chinese, the Koreans, and the Japanese are superstitious about the number four because it is a homonym for "death" in their languages. In Slavic mythology, the god Svetovid has four heads.
Presentation
IDF typically presents as a solitary painless, smooth, flesh-colored to red, dome-shaped nodule located on the dorsal or lateral aspect of a finger or toe but sparing the thumb or great toe; they occur principally in the first two years of life with about 1/3 of cases having a lesion since birth. However: 1) lesions with appearances similar to, and diagnosed as, IPF have been described in extra digital sites such as the arm, breast, tongue, thigh, and chest; 2) unusual cases have presented with multiple lesions, i.e. 2–3, uncommonly 7–15, and one case with 74 lesions in a 2018 review study; 3) cases have been reported in children up to the age 10 and one case was reported in a 52-year-old adult; 4) the lesions are typically smaller than 2 cm in maximum diameter but rarely have been tumor-sized, e.g. 4.5 cm; 5) the lesions, particularly when larger-sized, may be painful and/or compromise the functions of nearby joints and digits; and 6) the lesions occasionally invade the periosteum and erode a nearby bone. Pathology
Microscopic histopathological analyses of appropriately dye-stained IDF tissues typically show a non-encapsulated small tumor composed of bundles of uniform spindle-shaped cells that combine physical features of fibroblasts (the most common cell type in connective tissue) with those of myofibroblasts  (contractile, spindle-shaped cells that are identifiable by their expression of α-smooth muscle actin) in a background of collagen fibers. In hematoxylin and eosin-stained tissues, the spindle-shaped cells have pale eosinophilic (i.e.