Foolishness for Christ refers to behavior motivated by real or assumed craziness, to serve a religious purpose of Christianity. The term fools for Christ is attributed to Saint Paul. Saint Francis of Assisi and other saints acted the part of Holy Fools, as have the yurodivy of Eastern Orthodox asceticism. Fools for Christ often employ shocking, unconventional behavior to challenge accepted norms, deliver prophecies or to mask their piety. There are also parallels in non-Christian Oriental religion, notably amongst Zen monks, and the Mahasiddhas traditions.
Some prophets of the Old Testament, who had signs of strange behaviour, are considered to be predecessors of "Fools for Christ". Prophet Isaiah walked naked and barefooted about three years predicting a forthcoming captivity in Egypt Isaiah 20:2,3; prophet Ezekiel lay before a stone, which symbolized beleaguered Jerusalem, and ate a bread baked on human waste Ezekiel 4; Hosea married a harlot to symbolize the infidelity of Israel before God Hosea 3. The prophets were not counted as fools, as they just made separate actions to attract people's attention and to awake their repentance. All the above actions were reportedly inspired by God and corresponded to His will on prophet services.
According to Christian ideas, "foolishness" included consistent rejection of worldly cares and imitating Christ, who endured mockery and humiliation from the crowd. That's why, spiritual meaning of "foolishness" from the early ages of Christianity was close to unacceptance of common social rules of hypocrisy, brutality and thirst for power and gains.