According to McConkie and Millet, to “straiten” (1 Nephi 17:41) is to make narrow. The Lord, by the “rod of [his] mouth” (D&C 19:15), straitens Israel in order that they might walk in that path which is straight and narrow. [Joseph Fielding McConkie and Robert L. Millet, Doctrinal Commentary on the Book of Mormon, Vol. 1, p. 136]