Romans 12:9

Let love be without dissimulation
The apostle having given out suitable exhortations to the officers of this church, ministers and deacons, proceeds to stir up to the exercise of grace, and the discharge of such duties as were common to all the members of the church; and begins with "love", which is the cement of saints, and the bond of perfectness, without which all the gifts that men have, the profession they make, and works they do are of no avail, and they themselves nothing. Here it is to be taken, in the largest and most comprehensive sense, for love to God, Christ, the saints, and fellow creatures, and ought, with respect to each, to "be without dissimulation"; or "hypocrisy": love to God should be with all the heart, soul, and mind, otherwise the fear of him, and obedience to him, will be only outward, formal, customary, and hypocritical; love to Christ should be with sincerity, and so it is where it is right, hearty, and genuine; such can appeal to him as the searcher of hearts, that from the heart they love him; and love to one another should be not in word, and in tongue only, but in deed and in truth; yea, the love professed to fellow creatures, ought never to be through fear of men or mercenary views, but honest, upright, and sincere.

Abhor that which is evil;
sin, both in its principle and in its actings; it being hateful to God, Father, Son, and Spirit, contrary to the nature, being, and perfections of God, a transgression of his righteous law, exceeding sinful in itself, and pernicious in its effects and consequences; for all which it is to be abhorred by the saints: the word (apostugountev) , here used, designs the greatest aversation imaginable, a turning away from it, as what is the most loathsome, detestable, and abominable; and such an hatred of it with horror, as of the Stygian lake, or hell itself:

cleave to that which is good;
to God, who is originally, infinitely, and immutably good; who is good in his nature, and works, and to all his creatures, and especially his chosen people, and therefore should be cleaved unto; to his will, his ways, and worship; and to Christ the good shepherd of the sheep, the Lamb that is to be followed and cleaved unto, whithersoever he goes; and to the good Spirit of God, after whom we should walk, and not after the flesh; and to the good people of God, assembling with whom should not be forsaken; and to the good Gospel of Christ, and the truths of it, which should be held fast; and to the ordinances of the Gospel, which ought to be constantly attended on; and to every good work, to which we should be ready, careful to maintain, and ever follow, both among ourselves and all men: they should even be glued unto it, as the word here signifies.