7-2. The ordinary and perpetual classes of office in the Church are elders and deacons. Within the class of elder are the two orders of teaching elders and ruling elders. The elders jointly have the government and spiritual oversight of the Church, including teaching. Only those elders who are specially gifted, called and trained by God to preach may serve as teaching elders. The office of deacon is not one of rule, but rather of service both to the physical and spiritual needs of the people. In accord with Scripture, these offices are open to men only.

[DIGEST: The current PCA text dates to 1980 (M8GA, 8-88, p. 112), arising from a change proposed in 1979 by the Ad-Interim Committee on Number of Offices. For the full text of the Committee's report, see http://www.pcahistory.org/pca/2-455.html [M7GA, 7-23, pp. 77-85]. For a review of the long history of the Ad-Interim Committee on Number of Offices, see here.

BACKGROUND & COMPARISON:
PCA 1973, 7-2, Adopted text, (M1GA, Appendix, p. 130)
and
Continuing Presbyterian Church 1973, 7-2, Proposed text, p. 7
The whole polity of the Church consists in doctrine, government, and distribution. And the ordinary and perpetual officers in the Church, are, Teaching Elders, or Ministers of the Word, who are commissioned to preach the Gospel and administer the sacraments; Ruling Elders, whose office is to have the government and spiritual oversight of the church; and Deacons, whose office is to receive and administer the offering of the people. Both Teaching and Ruling Elders are known as Presbyters, and share equally in the governing of the Church.

PCUS 1933, VIII, § 31
The whole polity of the Church consists in doctrine, government, and distribution. And the ordinary and perpetual officers in the Church, are, Teaching Elders, or Ministers of the Word, who are commissioned to preach the Gospel and administer the sacraments; Ruling Elders, whose office is to have the government and spiritual oversight of the church; and Deacons, whose office is to receive and administer the offerings of the people.

PCUS 1879, IV-1-2
The whole polity of the Church consists in doctrine, government, and distribution. And the ordinary and perpetual officers in the Church are, Teaching Elders, or Ministers of the Word, who are commissioned to preach the gospel and administer the sacraments, and also to rule ; Ruling Elders, whose office is to wait on government ; and Deacons, whose function is the distribution of the offerings of the faithful for pious uses.

PCUS 1869 draft, IV-1-2
As the whole polity of the Church consisteth in doctrine, discipline, and distribution; so, the ordinary and perpetual officers in the Church are, Teaching Elders, who labor in the word and doctrine; Ruling Elders, who wait on government; and Deacons, whose chief function is the distribution of the offerings of the faithful.

PCUS 1867 draft, IV-1-2
As the whole polity of the church consisteth in doctrine, discipline, and distribution, so the ordinary and perpetual officers in the church are teaching elders, who labor in the word and doctrine; ruling elders, who wait on government; and deacons, whose chief function is the distribution of the oblations of the faithful. He that is called to teach is called also to rule, and he that is called to rule, is called also to distribute.

PCUSA 1789, II-a
The ordinary and perpetual officers, in the church, are, Bishops or Pastors[1]; the representatives of the people, usually styled Ruling Elders[2], and Deacons.[3]
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[1] 1 Tim. 3:1-2.--If a man desire the office of a bishop, he desireth a good work. Eph. 4:11. And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; ver. 12. For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ.
[2] I Tim. 5:17. Let the elders that rule well, be counted worthy of double honor.
[3] Phil. 1:1. To all the saints in Christ Jesus, which are at Philippi, with the bishops and deacons.

COMMENTARY:
F.P. Ramsay, Exposition of the Book of Church Order (1898, p. 45-46), on IV-1-2 :
33.--II. The whole polity of the Church consists in doctrine, government, and distribution.
By polity is meant activity as an organization. This whole activity consists in, or the sole work of the organized Church is limited to, doctrine, which is teaching or proclaiming the law of Christ revealed in the Scriptures; government, which is administering and enforcing this law (par. 17); and distribution, which is the application of the material offerings presented in the worship that the Church maintains in obedience to this law. And as the Church has nothing else to do but these three things, so it needs only the three classes of officers corresponding to these three functions.
And the ordinary and perpetual officers in the Church are, Teaching Elders, or Ministers of the Word, who are commissioned to preach the gospel and administer the sacraments, and also to rule ; Ruling Elders, whose office is to wait on government ; and Deacons, whose function is the distribution of the offerings of the faithful for pious uses.
The philosophy of the classification is this, that government and distribution are ways or means of teaching, or means of preserving the Church as a teaching organization ; and all the functions of the organized Church may be reduced to one, TEACHING and what is necessary thereto. The official teacher, then, has also ex officio the powers of government and distribution. So far as this teaching takes the form of ruling, there are joined with the teaching elders other elders, that, while not having the teaching office in its fullest scope, have it on its governmental side. And these officers, as rulers, must either themselves distribute the offerings, or have it done under their supervision ; and for this function the deacons are provided. It is, therefore, the office of the Deacons to relieve the Elders of the care of the secular affairs of the Church, and it is the office of the Ruling Elders to co-operate with the Teaching Elders in the governmental side of their work. (Administering the sacraments, being a form of teaching as distinguished from ruling, is reserved to the Teaching Elder.)