“To plead for purchased mercies, upon the strength of a promise, is a most useful exercise of faith, for promoting the spiritual life, and obtaining all the precious fruits and comforts of it. Did time allow, I might point out the usefulness, and give directions for the exercise of faith, in every circumstance in which you can be placed, and to obtain every mercy you need, for time or eternity, for yourselves or others, for individuals of the church in general. There is not a single case, with respect to which your prayers are required, but there is something in the promise suited to it, which you ought to hold up as a plea in prayer.

To illustrate this in a few instances only. Do you want pardon for backsliding and the cure of a backsliding temper? Plead that gracious promise, ‘I will heal their backsliding; I will love them freely.’ Do you lament that your souls are as barren heath in the desert, which does not see good when it cometh? Plead this and such like works of grace, ‘Their souls shall be as a watered garden.’ Do you feel your need of strength for duty and warfare? Hold up to Christ His own precious word, ‘My Grace is sufficient for thee.’ Do you long to see the prosperity of Zion and rejoice in Her joy? Plead the gracious promises of Zion’s God, ‘To make her a crown of glory in the hand of the Lord and a royal diadem in the hand of God.’ ‘To be as the dew to Israel, to make him revive as the corn, grow as the lily, and cast forth his roots as Lebanon.’

In this soul quickening exercise, faith looking to the mercy from which the promise originated, and the truth engaged for the performance of it, is strengthened to take hold of the Saviour; saying, ‘I will not let thee go, except thou bless me.’ Such a wrestling Jacob will become a prevailing Israel.” — John McMillan in Daniel M. Bennett, ed., Life and Work of Rev. John McMillan, D.D., Pioneer, Preacher, Educator, Patriot, of Western Pennsylvania (1935), p. 321