Anthony Norris Groves (1795 – 1853) stands as one of the great missionaries of the 19th century. Most people in today’s churches haven’t even heard of him.
Mission Societies vs. Churches
In that day, mission societies sent missionaries overseas, rather than the churches doing the sending themselves. In the early days of the modern missionary movement, mission societies were the sending agencies for cross-cultural missionaries, such as the Scottish Society for Propagating Christian Knowledge (1707), the Moravian Mission Society (1732) and the Baptist Mission Society (1792). The full name of the latter establishment was the Particular Baptist Society for Propagating the Gospel Among the Heathen (or, BMS). William Carey, “the father of modern missions, helped found it.
In 1795, the year Groves was born, a group of English Congregationalists (including David Livingstone and Robert Moffat), established the London Missionary Society (LMS).
Groves believed that, while the early missionary movement could be forgiven for their awkward method of sending out missionaries, churches should discover a better, more biblical way to do this. Scripture had convinced Groves that local churches must send out missionaries through the power of the Holy Spirit. Local committees and boards should not be the ones giving a salary to the missionary. Local churches must send and support the missionary.
A good example of this is the church in Antioch (Acts 13:1-3). They observed the ministry of Paul and Barnabas for at least a year. Then they set these men apart for their missionary work, praying and fasting before sending them on their way.
Five Reasons Churches Should Send Out Missionaries
Groves gave several reasons why he thought this was the best model. I will summarize some of them below.
First, churches that send out missionaries will know and love them intimately. The family crossing the globe isn’t just a face on a prayer card. The church is able to sympathize with their trials and rejoice with their success because they know them intimately.
Second, churches that send out missionaries will ensure they are qualified. Who is better prepared to judge a man’s character and ministerial gifts than the local church in which he has ministered? Prospective missionaries can easily fool outsiders. Not so with their local church. This is another reason why the modern method of individual families providing the majority of support for a missionary is so dangerous. There is little accountability.
Third, churches that send out missionaries will give more cheerfully. The Apostle Paul didn’t have to send weekly appeals for funds to the church in Philippi. Several in that church had been led to Christ by the riverside (Ac. 16:13). They knew and loved him. When he visited them, they were thrilled. When he needed help, they quickly sent Epaphroditus. Churches generally give the most to missionaries they know best.
Fourth, churches that send out missionaries give them freedom. They will pray for him. They will offer counsel. But contrary to a society, the church does not have a set of hard-and-fast rules the missionary must follow. They trust him and realize they do not know the culture or the difficulties as he does.
Fifth, churches that send out missionaries will not hamper him. There is no finance committee that must approve the decisions he makes. Speaking from experience, there are literally hundreds of ministry decisions I must make each year: purchasing a vehicle, locating a new preaching point, buying plane tickets, accepting a conference invitation, disciplining a backsliding believer. Churches that know their missionary and then send and support him, have much greater confidence that he will make the proper decisions. They are less likely to hinder him from reaching a conclusion quickly.
Conclusion
Groves wisely encouraged churches to take the lead in supporting and sending out missionaries. This does not preclude some of the advantages of mission boards, but it does emphasize the necessity for local congregations to know, love and judge their missionaries well before dispatching these evangelists around the world.
Between Two Cultures 
I agree biblically that the missionary should be sent from the church. As a missionary myself who has a sending church and is part of a parachurch missions organization as most modern missionaries are, I think there a few very practical reasons that being sent from a local church “through” a parachurch missions org is the common practice of today and the days of missionary societies which were very similar to modern parachurch missions orgs
1) missionary teammates (I teamed up with my current teammates through our parachurch org. They are all from different states so the likelihood of meeting them without our parachurch org seems slim. Some large churches could have enough aspiring missionaries to send their own team but may not, especially smaller churches. Also, it’s not just the missionary teammates you group up with BEFORE going to the field, but bigger parachurch missions orgs will already have missionaries on the field that you can go join so unless you are pioneering an area that has zero missionaries, you can go join someone else and learn from them as you work under/alongside them.
2) missionary training – my local church never had veteran missionaries come and train aspiring missionaries but we received weeks of classroom training with veteran missionaries through our parachurch org.
3) missionary logistics – related to having the advice of a veteran missionary above, a missions org typically has experience and knowledge in various thing that a local church doesn’t typically have i.e. immigration system for country X, language learning training/techniques.
4) fundraising – if a local church can only financially support 1 missionary family in total (let’s say that costs $60,000 usd a year) then sending through a parachurch missions org may help the church send more missionaries because missionary candidate 2,3, and 4, that the local church can’t financially support in total because they are already using all of their funds to support family 1, can join a parachurch missions org and through their network of other churches that want to give to missionaries but God hasn’t raised up any from among them to send, receive the financial support they need. (those last few sentences were a grammatical mess but hopefully you can understand what I’m saying)
So banking off your recent post about former missionaries making the best missiologists, I agree and will say that it’s typically it’s easier to find current and former missionaries to learn from, be trained by, and team up with at a parachurch missions org than in one local church. Of course there are many exceptions to this but because this is a typical norm, parachurch missions orgs continue to abound while finding a missionary with JUST a sending church and no connection to a parachurch missions org is more rare.
And while there’s plenty of overlap and things to hash out, being sent by a local church vs being a part of a parachurch missions org is not an either / or IF the local church does the sending THROUGH the parachurch missions org and they are acknowledged and treated as the SENDER by the missions org.
In the missions org I am a part of, the acknowledgement that the sending church is the sender is there but I think the missions org still makes decisions as the “boss” for the missionaries instead of the sending church or the missionary themselves which CAN step on the sending church’s / missionary’s toes BUT it can also be more helpful and provide something good that the sending church may not be able to.