Ralph Erskine (Self-conceit dissected), Sermons 1:386:
The first antidote against self-conceit is, “To look well to ourselves, and our foul faces, in the glass of the holy law.” Many may vainly imagine their faces fair and clean till they come to look in a glass; and they no sooner look therein, but they see many spots and defilements which before they thought not of. So let us do here. Let us examine ourselves by the law; examine what, and how much the law requires; and how far short we come of that purity, grace, and holiness that is there required: and then you will find little cause of falling in love with your Ethiopian face, or dote upon yourselves, when you see that you are so ugly and deformed. A sight of your deformity would keep you from self-conceit. When, in the glass of the law, you see your own defiled and deformed visage and monstrous shape, you will find little cause to be enamoured with your own beauty. Men are pure in their own eyes because they do not make use of this looking glass. When the commandment came, and Paul saw himself in this glass, then sin revived, and he died to all conceit of his own purity. When you view yourself in this glass, it will make you say the quite contrary to the young man in the gospel: None of all these things have I kept from my youth.
The first antidote against self-conceit is, “To look well to ourselves, and our foul faces, in the glass of the holy law.” Many may vainly imagine their faces fair and clean till they come to look in a glass; and they no sooner look therein, but they see many spots and defilements which before they thought not of. So let us do here. Let us examine ourselves by the law; examine what, and how much the law requires; and how far short we come of that purity, grace, and holiness that is there required: and then you will find little cause of falling in love with your Ethiopian face, or dote upon yourselves, when you see that you are so ugly and deformed. A sight of your deformity would keep you from self-conceit. When, in the glass of the law, you see your own defiled and deformed visage and monstrous shape, you will find little cause to be enamoured with your own beauty. Men are pure in their own eyes because they do not make use of this looking glass. When the commandment came, and Paul saw himself in this glass, then sin revived, and he died to all conceit of his own purity. When you view yourself in this glass, it will make you say the quite contrary to the young man in the gospel: None of all these things have I kept from my youth.