In answer to the op question, I think this is an application of the following:
1 Corinthians 7.24: "Brethren, let each one remain with God in that state in which he was called."
Although the context is not ordained ministry, certainly if this is applicable to calling in general, it is likewise applicable to the calling of ministry.
The other point, already mentioned but worthy of expansion, is that Scripturally the bishop or deacon must be (already at ordination) the husband of one wife (1 Timothy 3.2,.12). The reasoning is simple: either one is avowed to celibacy, or one is still a bachelor. A bachelor looking to marry in the future is untested as to how he rules his own house. The one who is to be appointed as a leader within a local Church therefore must be "one who rules his own house well...for if a man does not know how to rule his own house, how will he take care of the church of God?" (1 Tim. 3.4).
In Titus it is stated as a clear prerequiste for a Presbyter that those who are to be ordained to community churches must already be "the husband of one wife" if they are to be considered as candidates for the Presbytery/Episcopacy, and not "bachelors" looking to marry but untested with marriage:
Titus 1.5ff "For this reason I left you in Crete, that you should set in order the things that are lacking, and appoint presbyters in every city as I commanded you—if a man is blameless, the husband of one wife, having faithful children not accused of dissipation or insubordination. For a bishop must be blameless, as a steward of God, not self-willed, not quick-tempered, not given to wine, not violent, not greedy for money, but hospitable, a lover of what is good, sober-minded, just, holy, self-controlled, holding fast the faithful word as he has been taught, that he may be able, by sound doctrine, both to exhort and convict those who contradict."