Why should the children of a [the] King. I. Watts. [Assurance through Faith.] Published in his Hymns and Spiritual Songs, 1709, Bk. i., No. 144, in 4 stanzas of 4 lines, and headed, "The Witnessing and Sealing Spirit." It was adopted by G. Whitefield in his Collection of Hymns, &c, 1753; A. M. Toplady in his Psalms & Hymns, 1776, and others amongst the older compilers. It is also widely used in Great Britain and America.
--John Julian, Dictionary of Hymnology (1907)