(David) Advocates of an inclusive diaconate in the PCA show greatest disdain for primary sources not in their treatment of the works of men but in their handling of the Word of God. If it's embarrassing to misread Warfield, it's shameful to permit a tendentious view to warp our teaching of God's Word.
Where is this failure most evident in the arguments of advocates of mixed diaconates?
First, in claiming the office of "deaconess" for Phoebe while generally denying that office to the seven selected to serve the needs of widows in Acts 6, advocates of a mixed diaconate display a troublingly selective approach to what constitutes the office of deacon in Scripture.
Though it's true that the seven of Acts 6 are never called deacons, Luke's description of their ordination and work so closely mirrors the calling and tasks associated with the diaconal office in 1 Timothy 3 and 4 that for millennia the Church has assumed these men to be the original biblical deacons. Yet advocates of a mixed diaconate frequently deny the office of deacon to the seven because of the obvious authority they wielded both in Word and deed (think of Stephen and Philip's subsequent ministry in Acts).
Phoebe, on the other hand, they declare an official member of the office on the basis of Paul calling her a deaconess--a word that in the absence of any description of her service could equally (and most likely does) mean that she served the church, literally, as a "servant" in keeping with Christ's call to servanthood for all His disciples.
Second, arguments for a mixed diaconate in the PCA inherently claim the Biblical necessity of PCA polity and deny all other views--even the views of many other equally Reformed bodies across the centuries. Why? because the office of elder must contain both pastors and laymen if the office of deacon is to be rendered so devoid of authority that a church which claims to be complementarian can ordain women to the diaconal office without obvious hypocrisy.
If, however, there is the slightest chance that the PCA's particular two-office view is not the sole and perfect representation of Biblical polity, if, for example, the Scottish Reformed church is even possibly correct in ordaining pastors as elders and lay leadership to the diaconate, then arguments for a mixed diaconate (at least in the context of the officially complementarian PCA) become hubristic claims for the perfection of PCA polity--claims even the Westminster divines were unwilling to make for an office they simply called "church governor" because of divisions in their midst over whether the office the PCA calls "ruling elder" actually possesses New Testament warrant.
In the end, it's impossible to argue the office of deacon without assuming a particular understanding of the office of elder. As Iain Murray demonstrates in his article on the controverted history of the office of elder in the Reformed church, any view of the diaconal office which denies it ecclesiastical authority is provincial--and in the context of the debate over female deacons, tendentious to boot.
Finally, and most troublingly, advocates of a mixed diaconate studiously ignore the implications of Paul's statement about deacons who serve well in 1 Timothy 3:13:
"For those who have served well as deacons obtain for themselves a good standing and great boldness in the faith that is in Christ Jesus."
The Greek word (παρρησία) translated "great boldness" by the KJV is defined by Strong's as "freedom in speaking, unreservedness in speech." Kittel says of Luke's use of the word in Acts, "Παρρησία is so closely related to the λαλεῖν or διδάσκειν of the apostles that παρρησιάζεσθαι almost takes on the sense 'to preach,' cf. 9:27, 14:3, 18:26, 19:8
Kittel says of παρρησία in 1 Timothy 3:13, "The reference... is to παρρησία towards God and men. If we are to expound παρρησία here with reference to that wherein it finds expression, then it is the 'unhampered and joyful word, both in prayer and in dealings with men.' It presupposes καλῶς διακονεῖν and is grounded ἐν πίστει τῇ ἐν Χριστῷ Ἰησοῦ."
Indeed, such boldness is immediately evident in Stephen's sermon before the Sanhedrin in Acts 7 following faithful service as a deacon in Acts 6.
Calvin says in his commentary on 1 Timothy 3:13,
...this passage has been commonly interpreted as describing elevation to a higher rank, as if the Apostle called to the honor of being presbyters those who had faithfully discharged the office of a deacon. For my own part, though I do not deny that the order of deacons might sometimes be the nursery out of which presbyters were taken, yet I take Paul’s words as meaning, more simply, that they who have discharged this ministry in a proper manner are worthy of no small honor; because it is not a mean employment, but a highly honorable office. Now by this expression he intimates how much it is for the advantage of the Church to have this office discharged by choice men; because the holy discharge of it procures esteem and reverence.
We would do far better exegetically to imitate Calvin in provisionally accepting the early Church's view of the diaconate as a nursery for presbyters than to diminish the authority of the diaconate by making it radically less than the eldership.
In the end, the argument over female deacons is a biblical argument, and it's in their handling of Scripture that advocates of female deacons show greatest disdain for Primary Sources.