The unlawfulness of istizlal (standing in the shadow) is one of the indisputable issues of Shiah Jurisprudence that Imam khomeini’s antecedents had no expiliclt decree in this regard, so it is one of the peculiar decrees of Imam khomeini following whom most of the Maraji (supreme religious authorties) accepted his view. Owing to the importance of the issue, the author of this article tries to examine this issue whith reference to certain narrrations. These narrations are of four kinds as follows:
A) Those narrations in which covering from the sun are prohibitted.
B) Those narrations which used the word idha.
C) Those narrations which consider istizlal and idha as unlawful and
     some   of the people used these words and their derivatives.
D) Some of the narrations are used to consider istizlal as unlawful, that
      is, those narrations according to which sitting under a dome or in a
      synagogue is prohibitted.
Moverover, this article referes to various meanings of istizlal in different cultures and at the end it is concluded that they do not prohibit to go under the umbrella in the night, so we can say that is lawful.