In the Epistles, we find the exposition of the result of that glorious work of grace, by which man is placed on entirely new ground with God, in reconciliation with Him; as well as the development of the counsels of God in Christ, according to which this new world is established and ordered. In giving this exposition of the ways of God in connection with the work which is their basis, the perfect efficacy of the work itself, and the order of our relations with God, are plainly set forth; so that the whole system, the whole plan of God, and the way in which it was put in execution, are presented. And in doing this, that which man is, that which God is, that which eternal life is, are clearly put before us.
The death and resurrection of Christ, as well as His exaltation to the right hand of God, form the centre of all this instruction.
There are three great divisions in this instruction, which are connected in general with the instrument used of God in the communication of each part.
1st. The counsels of God, which are developed by Paul in connection with the revelation of true righteousness before God, the ground on which a man can be truly righteous before God-God's righteousness, man being a sinner.
2nd. The life of God, eternal life manifested and imparted. This is in John's epistle. 
3rd. Christian life on the earth, in following a risen Christ. This we find in the Epistle of Peter, in connection with God's government of the world as such: the Christian is a pilgrim. There are also James and Jude. The first presents moral life-the life of faith on earth-as the true demonstration to men of our faith, and, in particular, of practical faith in Christ as well as in God, who answers our requests and our wants. On this account, while clearly and distinctly recognising faith in Christ, and our being begotten by the mighty grace of God through His word, this epistle scarcely rises in fact above such life as could have manifested and developed itself at any period whatsoever in a believer; only that it was the Christian, born of God, who now exemplified it, and that thus it was the law of liberty, because the new nature and the will of God ran together, and both were fully revealed in Christ. Thus the Epistle of James is linked with the synagogue, and with Christians still in connection with Judaism, as we have seen them historically at Jerusalem with James at their head. The Epistle does not go beyond that position. It is the last testimony rendered to Israel looked at as the people of God, while at the same time distinguishing the quickened remnant who had faith in Christ, although they were not yet separated from the nation. Our habits of thought, founded not on imposed law without reason, but upon a much more complete development of Christianity (a development which was the manifestation of counsels much more ancient than the Jewish nation, for they were the eternal counsels of God), make it difficult for us to apprehend this form of the truth-a form in which it is connected with that which, because of the promises made to Israel, was historically its cradle here below.
If we have rightly understood the history of the Acts, it will make the position of believers, as we find it in the Epistle of James, much more intelligible to us. The Epistle is a correction of profession without life, and most valuable in this respect.
Jude has a very different character. It is not the cradle of Christianity, or of the assembly on earth: it is its decay and its death here below. It does not keep its first estate. This Epistle resembles a part of the second by Peter; but the latter speaks of the judgment brought in by the general government of God; Jude, of the fall of that which has had its existence since Pentecost under the eye of God, as responsible for the maintenance of the glory of His grace on the earth-a fall which, with regard to the present state of things, brings on the judgment of which Peter speaks, and which he carries on even to the dissolution of the earth and its elements. The evil that had already begun in its earliest germs gave rise to this development in Jude, and to the distinction of the true assembly, or at least of its members, who would be presented in glory before the presence of the Lord in heaven. The Epistle to the Hebrews views the saint on earth, perfected as to acceptance by the work of Christ, and as having thus boldness to enter into the holiest, but as walking in weakness here on the earth, not united to Christ in heaven; hence it sets forth the priesthood of Christ as obtaining grace to help in time of need, while He appears always in the presence of God for us. It is not intercession in respect of sins (we have no more conscience of sins), but grace and help for us, such as we are. Christ's Person as God and man also is very fully brought out.
A more complete and more precise development will be found in studying the Epistles themselves.
We will begin with the Epistles of Paul. In the historical character of their doctrine James and Peter should precede them; this is to say, in the progress of the manifestations of God's counsels in their whole extent. But as developing the foundations of truth, and laying open its range as a whole, the Epistles of Paul have evidently the first place and throw light on that of the others. The Epistle to the Romans especially establishes the grand foundations of divine truth, and individual relationship with God, in the most plain and complete manner, so that we have no motive for deviating from the order in which we find them habitually placed. There is nothing in that order which, as to its details, is connected with any moral or chronological reason: it differs also in different countries and in different versions; but it is most convenient to take that order which the reader will find in his ordinary Bible. We may notice that which will be interesting in this respect as we study each epistle. It is probable that among the epistles of Paul that to the Thessalonians was the first. The date of the Epistle to the Galatians is less certain, but it was written after several years of labour; the two to the Corinthians, and that to the Romans, at Ephesus, Macedonia, and Corinth, respectively, during his journey round the Archipelago after his long sojourn at Ephesus; those to the Ephesians, Philippians, and Colossians, during his captivity. I reserve the others, Hebrews included, for the study of those epistles, pointing out only that which it may be useful to know in those of which the date is pretty certain.
The First Epistle of John, we may add, hardly belongs to any particular period, save that (in setting forth the nature and character of the life of God, the touchstone of all profession, and safeguard against all error, against all that does not bear its stamp, and against all the pretensions which, being devoid of it, betray themselves by that very fact) this epistle supposes the entrance of these errors, and thus the latter days of the apostolic age. And this indeed is more or less the case with the epistles called catholic, from not being addressed to any particular assembly, as Paul's, the master-builder's, were. In these we find prophecies of the evil from the very first, and the fact that the mystery of iniquity was at work already. But the catholic epistles take that ground. Jude speaks of corruption entering in, John of apostates going out.
Let us now consider a little the epistles of Paul himself. They have more than one character, whilst all displaying that spirit gifted from on high, which expatiates on the wide range of the thoughts of God, and in its wonderful energy can enter at the same time into every detail, even into those of individual life; that knows how to place itself exactly in the relations of a fugitive slave with his master, in view of grace, and to set forth with divine clearness all the counsels by which the Father glorifies His Son, by making Him the centre of all His purposes, of the system which results from the exercises of all His power.
The care of the assemblies, the development of the counsels of God, the exercise of brotherly affection, have each their place in his thoughts and his labours; while he is often forced to develop the truth in striving against errors which rend his heart, whether he thinks of the Christ whom they dishonour, and of the truth-the instrument of salvation-which they undermine; or whether he remembers the dear redeemed ones of Christ who are troubled by these errors, perhaps turned aside from the true path by them.
 Paul's writings present man to God in and through Christ. John's Gospel presents God to man in Christ; the Epistles unfold divine life in Christ communicated to the believer; though Paul of course speaks of life, and John of man as in Christ before God. We must add for John's Gospel the coming of the Comforter. The reader will remark also that John's Gospel presents to us the new thing taking the place of Judaism, especially from chapter 4. Election runs all through it, very strongly expressed. The synoptical Gospels present Christ to the Jews, to man, to be received; but the world and the Jews are judged in John 1: 10, 11. From that, our grace and the elect remnant, the sheep alone, are recognised, and the Jews treated as reprobate.