be at variance

References in classic literature ?
Dear Sir,-- "The disagreement subsisting between yourself and my late honoured father always gave me much uneasiness, and since I have had the misfortune to lose him, I have frequently wished to heal the breach; but for some time I was kept back by my own doubts, fearing lest it might seem disrespectful to his memory for me to be on good terms with anyone with whom it had always pleased him to be at variance,-- There, Mrs.
Alliance by blood, or marriage, is a frequent cause of war between princes; and the nearer the kindred is, the greater their disposition to quarrel; poor nations are hungry, and rich nations are proud; and pride and hunger will ever be at variance.
On points where the learned have, in purity of heart, been compelled to differ, the unlettered will necessarily be at variance.