David Clarkson (Select Works, 420-421):
They ascribe to him a will of universal salvation; when they discern it can be no other than a mere velleity, an incomplete intention, a weak, ineffectual desire, a faint and fruitless wishing of such general happiness, when he knows it will never be effected, and is resolved not to take the course to effect it. This is such a mercy, as jostles out and clashes with his other perfections, and is inconsistent with his knowledge, power, sincerity, wisdom, blessedness, and mercy itself in the true notion of it.
With his knowledge; for who will desire and design that, which he knows will never be effected? With his power; for who will not effect that, which he really intends and designs, if he be able? With his sincerity; for what ingenuous person will pretend to desire and design that which he never means to bring about? With his wisdom; for who will propose to himself an end, and never intend the means which are proper, and alone sufficient to obtain it? With his blessedness; for to fall short continually of what one desires and intends, is an unhappiness. With the nature of Divine mercy and goodness; for that is not real goodness, which does no good, or not the good it makes show of. That is not saving mercy indeed, which leaves the objects of it miserable, when it can relieve them; that wishes them well, but lets them perish eternally. But that which they ascribe to God, is such a mercy, as can well digest the everlasting misery of all mankind: such a love, such a goodness, as could be satisfied, if not one person in the world should be saved.
Source: http://www.puritanboard.com/f48/universal-will-salvation-destroys-mercy-83253/, Comment #1 (Thank You, Reverend Winzer!)