Systematical Divinity, I am sensible, is now become very unpopular. Formulas and articles of faith, creeds, confessions, catechisms, and summaries of divine truths, are greatly decried in our age; and yet, what art or science soever but has been reduced to a system? physic, metaphysic, logic, rhetoric, &c. Philosophy in general has had its several systems; not to take notice of the various sects and systems of philosophy in ancient times; in the last age, the Cartesian system of philosophy greatly obtained, as the Newtonian system now does. Astronomy in particular has been considered as a system: sometimes called the system of the universe, and sometimes the solar, or planetary system: the first that is known is what was brought by Pythagoras into Greece and Italy, and from him called the Pythagorean system; and which was followed by many of the first and ancient philosophers, though for many years it lay neglected; but has been of late ages revived, and now much in vogue: the next is the Ptolemaic system, advanced by Ptolemy; which places the earth in the centre of the universe; and makes the heavens, with the sun, moon, and stars, to revolve about it; and which was universally embraced for many hundreds of years, till the Pythagorean system was revived by Copernicus, two or three hundred years ago, called, from him, the Copernican system. In short, medicine, jurisprudence, or law, and every art and science, are reduced to a system or body; which is no other than an assemblage or composition of the several doctrines or parts of a science; and why should divinity, the most noble science, be without a system? Evangelical truths are spread and scattered about in the sacred Scriptures; and to gather them together, and dispose of them in a regular, orderly method, surely cannot be disagreeable; but must be useful, for the more clear and perspicuous understanding them, for the better retaining them in memory, and to show the connexion, harmony, and agreement of them. Accordingly we find that Christian writers, in ancient times, attempted something of this nature; as the several formulas of faith, symbols or creeds, made in the first three or four centuries of Christianity; the Stromata of Clemens of Alexandria; the four books of Principles, by Origen; the divine Institutions of Lactantius; the large Catechism of Gregory Nyssene; the Theology of Gregory Nazianzen; the Exposition of the Apostles’ Symbol, by Ruffinus; and the Enchiridion of Austin, with many others that followed: and since the Reformation, we have had bodies or systems of divinity, and confessions of faith, better digested, and drawn up with greater accuracy and consistence; and which have been very serviceable to lead men into the knowledge of evangelical doctrine, and confirm them in it; as well as to show the agreement and harmony of sound divines and churches, in the more principal parts of it: and even those who now cry out against systems, confessions, and creeds, their predecessors had those of their own; Arius had his creed; and the Socinians have their catechism, the Racovian catechism; and the Remonstrants have published their confession of faith; not to take notice of the several bodies of divinity published by Episcopius, Limborch, Curcellæus, and others. The Jews, in imitation of the Christians, have reduced their theology to certain heads or articles of faith; the chief, if not the first that took this method, was the famous Maimonides, who comprised their religious tenets in thirteen articles; after him R. Joseph Albo reduced them to three classes, the existence of God, the law of Moses, and the doctrine of rewards and punishments.

But what makes most for our purpose, and is worthy of our example, are the Scripture compendiums or systems of doctrine and duty. What a compendium or body of laws is the decalogue or ten commands, drawn up and calculated more especially for the use of the Jews, and suited to their circumstances! a body of laws not to be equalled by the wisest legislators of Greece and Rome, Minos, Lycurgus, Zaleucus, and Numa; nor by the laws of the twelve Roman tables, for order and regularity, for clearness and perspicuity, for comprehensiveness and brevity; being divided into two tables in the most perfect order; the first respecting the worship of God and the duties owing to him, and the other respecting men and the mutual duties they owe to each other. As prayer is a very principal and incumbent duty on men with respect to God, our Lord has given a very compendious directory, as to the matter of it, in what is commonly called the Lord’s prayer; which consists of petitions the most full, proper, and pertinent, and in the most regular order. And as to articles of faith or things to be believed, we have a creed made mention of in Heb. 6:1, 2; consisting of six articles, repentance from dead works, faith towards God, the doctrine of baptisms, and of laying on of hands, the resurrection of the dead, and eternal judgment. These are commonly thought to be so many articles of the Christian faith; but I rather think they are so many articles of the Jewish creed, embraced and professed by believers under the Jewish dispensation; since the Christian Hebrews are directed to consider them as the principles of the doctrine of Christ, as an introduction, and as leading on to it, and which were in some sense to be left and not laid again; they were not to stick and stop here, but to go on to perfection, by searching into and embracing doctrines more sublime and perfect, revealed in the gospel; at least they were not to be any longer instructed in the above articles in the manner they had been, but in a clearer manner, unattended with legal ceremonies, to view them and make use of them. Thus for instance, they, the believers, Christian Hebrews, were not to learn the doctrine of repentance from slain beasts, or to signify it by them, as they had been used to do; for every sacrifice brought for sin, which they were no longer obliged to, was a tacit confession and an acknowledgment of sin, and that they repented of it, and deserved to die as the creature did; but now they were to exercise evangelical repentance in the view of a crucified Christ, and remission of sin by his blood: and whereas they had been taught to have faith towards God, as the God of Israel, they were now moreover to believe in Christ as the Son of God, the true Messiah, the Saviour of lost sinners, without the intervention of sacrifices, see John 14:1. The doctrine of baptisms is to be understood of the divers baptisms, or bathings among the Jews, spoken of in Heb. 9:10; which had a doctrine in them, teaching the cleansing virtue of the blood of Christ to wash in for sin and for uncleanness; which they were no more to learn in this way, but to apply immediately to the blood of Christ for it. And the doctrine of laying on of hands, respects the laying on of the hands of the priests and people on the heads of the sacrifices, which instructed in that great and evangelical truth, the transfer and imputation of sin to Christ offered up in the room and stead of his people; and which was to be taught and learnt no longer in that manner, since Christ was now made sin for his people, and had had their sins imputed to him, which he had borne in his own body on the tree: and as for the doctrines of the resurrection of the dead, and eternal judgment, they were such as distinguished Jews and Gentiles, which latter were greatly strangers to a future state; and though they were common to Jews and Christians, yet the believing Hebrews were not to rest in the knowledge they had of these, as enjoyed under the former dispensation; but to go on to perfection; and to press forward towards a greater share of knowledge of them and of other more sublime doctrines; since life and immortality were brought to life by Christ in a clearer and brighter manner through the gospel. But all that I mean by this is, that the principal doctrines of faith under the Jewish dispensation are reduced to a system, though to be improved and perfected under the gospel dispensation. Those articles were but few; though Gregory observes, that according to the increase of times, the knowledge of saints increased, and the nearer they were to the coming of the Saviour, the more fully they perceived the mysteries of salvation: and so the articles in the formulas and symbols of the first Christians were but few, suitable to the times in which they lived, and as opposite to the errors then broached; and which were increased by new errors that sprang up, which made an increase of articles necessary; otherwise the same articles of faith were believed by the ancients as by the later posterity. It is easy to observe, that the first summaries of faith recorded by the most ancient writers went no farther than the doctrine of the Trinity, or what concerns the three Divine Persons; the doctrines of the heretics of the first ages being opposed to one or other of them: but when other heresies sprang up and other false doctrines were taught, it became necessary to add new articles, both to explain, defend, and secure truth, and to distinguish those who were sound in the faith of the gospel, from those that were not.

John Gill, A Complete Body of Doctrinal and Practical Divinity: Or A System of Evangelical Truths, Deduced from the Sacred Scriptures, New Edition., vol. 1 (Tegg & Company, 1839), viii–xii.