Indicating that one will as opposed to being permissible (will vs. may.)
Law Dictionary – Alternative Legal Definition
As used in statutes and similar instruments, this word is generally imperative or mandatory; but it may be construed as merely permissive or directory, (as equivalent to “may,”) to carry out the legislative intention and in cases where no right or benefit to any one depends on its being taken in the imperative sense, and where no public or private right is impaired by its interpretation in the other sense. Also, as against the government, “shall” is to be construed as “may,” unless a contrary intention is manifest.