Warnings by C. H. Spurgeon From the August 1884 Sword and Trowel

Y KEEPING OUR EYES OPEN, and judging things upon Scriptural principles, we may often be forewarned in our dealings with certain characters. One man cannot see further into a millstone than another, and yet shrewdness sees where the ordinary observer is in the dark. A prudent man, with the fear of God before his eyes, is almost a prophet. Two or three instances are before our mind at this moment.
A gentleman went carefully into the stable where his horse was placed to bait, and he saw for himself that the proper feed of corn was in the manger. In a few minutes' time he was in the stable again, and the oats were gone. He taxed the hostler with taking them out, and remained while he saw his nag eat up his fair portion. How did he know that the hostler would steal the corn? He had heard him cursing, and therefore he knew that he would steal.
A friend met the deacon of a church in the street—a man whom he much esteemed. The aforesaid deacon begged the loan of £100, and the friend would have lent it to him with pleasure; but in the course of conversation the deacon observed, "Other people might rob you; but you know me as an old pilgrim. I am, I trust, quite past temptation." The money was refused, for the friend said to himself, "Past temptation? Past temptation? Why, he must be quite ignorant of his own heart. He must surely be a hypocrite." And so he was. He knew that he was hopelessly involved even when he was seeking a loan from one who could not afford to lose the money: before that day was over he had failed. "Pride goeth before destruction." "A prating fool shall fall." His Bible had made our friend wise, and he was saved from loss.
A man who stood high in the city observed, with great satisfaction, that he had in a single morning cleared £30,000 by a speculation. A brother merchant remarked that he ought to be very grateful to Providence for such good fortune; whereupon the successful merchant snapped his fingers, and said, "Providence! pooh! that for Providence! I can do a deal better for myself than Providence can ever do for me." He who heard the observation walked away, and resolved never to deal with such a man again except upon cash principles, for he felt sure that a crash would come sooner or later. Great was the indignation of the man who stood high in the city when he was told, "If you and I are to have dealings it must be on strictly ready-money terms." He was insulted; he would not endure it; he would go to another house. That other house welcomed his custom, and in due time it was repaid by losing many thousands.
A tradesman chose a shopman from seeing him pick up a pin; Rowland Hill would button up his coat when he heard a man swear, for he did not want to have his pocket picked: thus for good or for evil little things may be tests of character. To deal with persons who have no respect for the Sabbath is always risky; to marry a man who can repeat a lewd story is eminently perilous; to buy goods of tradesmen who are "really giving them away" is to invite deception; and to trust those who flatter you is to court delusion. Do you meet with one who tells you many of the secret faults of others? Mind that you show him none of your own which you would not wish to publish. Does he tell you what others have said of you? Then say nothing of others which you would not wish him to report; for as sure as you live he will repeat all that you say, with additions. All dogs that fetch will carry.
By observing such things as these, men may be saved from deceptions. The difference between one man and another, in point of prudence, mainly arises from the fact that one man learns from his blunders and another does not. When we are once taken in by a person, we ought to take his measure so exactly that he will not be able to do it again. No mouse can be excused if it is caught twice by the same cat. Yet as long as the world stands, there will remain some in it who can never see further than the end of their own noses.