How do Christians who adhere to the maxim “in essentials unity; in non-essentials liberty; and in all things charity” determine what is essential?

I would like to go to the origins as far as possible and try to understand what the presumed author meant by this diction.

He discusses the difference between necessaria and nonnecessaria.

How do Christians who adhere to the maxim “in essentials unity; in non-essentials liberty; and in all things charity” determine what is essential?

I would like to go to the origins as far as possible and try to understand what the presumed author meant by this diction.

The authorship has recently been traced to Rupertus Meldenius, an orthodox Lutheran, and not St. Augustine.

He discusses the difference between necessaria and nonnecessaria.

Necessary dogmas are:

• (1) articles of faith necessary to salvation;
• (2) articles derived from clear testimonies of the Bible;
• (3) articles decided by the whole church in a synod or symbol;
• (4) articles held by all orthodox divines as necessary.

Not necessary, are dogmas:

• (1) not contained in the Bible;
• (2) not belonging to the common inheritance of faith;
• (3) not unanimously taught by theologians;
• (4) left doubtful by grave divines;
• (5) not tending to piety, charity, and edification.

Let all be done through charity. Love will cover a multitude of sin. See: 1 Peter 4:8

The authorship has recently been traced to Rupertus Medendius an otherwise unknown divine, and author of a remarkable tract in which the sentence first occurs. He gave classical expression to the irenic sentiments of such divines as Calixtus of Helmstadt, David Pareus of Heidelberg, Crocius of Marburg, John Valentin Andreae of Wuerttemberg, John Arnd of Zelle, Georg Frank of Francfort-on-the-Oder, the brothers Bergius in Brandenburg, and of the indefatigable traveling evangelist of Christian union, John Dury, and Richard Baxter. The tract of Meldenius bears the title, Paraenesis votiva pro Pace Ecclesiae ad Theologos Augustanae Confessionis, Auctore Ruperto Meldenio Theologo, 62 pp. in 4to, without date and place of publication. It probably appeared in 1627 at Francfort-on-the-Oder, which was at that time the seat of theological moderation. Mr. C. R. Gillett (librarian of the Union Theological Seminary) informs me that the original copy, which he saw in Berlin, came from the University of Francfort-on-the-Oder after its transfer to Breslau.

The author of this tract is an orthodox Lutheran, who was far from the idea of ecclesiastical union, but anxious for the peace of the church and zealous for practical scriptural piety in place of the dry and barren scholasticism of his time. He belongs, as Luecke says ("Stud. und Kritiken," 1851, p. 906), to the circle of "those noble, genial, and hearty evangelical divines, like John Arnd, Valentin Andrea,, and others, who deeply felt the awful misery of the fatherland, and especially the inner distractions of the church in their age, but who knew also and pointed out the way of salvation and peace." He was evidently a highly cultivated scholar, at home in Hebrew, Greek, and Latin, and in controversial theology. He excels in taste and style the forbidding literature of his age. He condemns the pharisaical hypocrisy, the philodoxia, philargia, and philoneikia of the theologians, and exhorts them first of all to humility and love. By too much controversy about the truth, we are in danger of losing the truth itself. Nimium altercando amittitur Veritas. "Many," he says, "contend for the corporal presence of Christ who have not Christ in their hearts." He sees no other way to concord than by rallying around the living Christ as the source of spiritual life. He dwells on the nature of God as love, and the prime duty of Christians to love one another, and comments on the seraphic chapter of Paul on charity (1 Cor. 13). He discusses the difference between necessaria and nonnecessaria. Necessary dogmas are, (1) articles of faith necessary to salvation; (2) articles derived from clear testimonies of the Bible; (3) articles decided by the whole church in a synod or symbol; (4) articles held by all orthodox divines as necessary. Not necessary, are dogmas (1) not contained in the Bible; (2) not belonging to the common inheritance of faith; (3) not unanimously taught by theologians; (4) left doubtful by grave divines; (5) not tending to piety, charity, and edification. He concludes with a defense of John Arnd (1555-1621), the famous author of "True Christianity," against the attacks of orthodox fanatics, and with a fervent and touching prayer to Christ to come to the rescue of his troubled church (Rev. 22: 17).

He concludes the discussion with this exhortation:-

"Summa est.: Servemus in necessariis unitatem,in non-necessariis libertatem, in utrisque charitatem." - A common quotation from "Augustine"?

The maxim “in essentials unity; in non-essentials liberty; and in all things charity” is widely embraced by many Protestant churches (Church of England/Anglican, Methodist, Evangelical Presbyterian, Moravian, etc.). The phrase in its current form is found in Pope John XXIII's encyclical Ad Petri Cathedram of 29 June 1959, where he uses it favorably. In the United Methodist Church Book of Discipline, the phrase appears in the doctrinal history section: 57 as "In essentials, unity; in non-essentials, liberty; and in all things, charity." A few lines later, the mandate is emphasized as "the crucial matter in religion is steadfast love for God and neighbor, empowered by the redeeming and sanctifying work of the Holy Spirit." (Taken from the Wikipedia article you based your question on.)

That is possibly the short answer to your question. However, it’s not as simple as that, more is the pity. Before moving on to doctrinal issues, please be aware that failure by one denomination to accept the essential doctrines upheld by Christian churches does not necessarily “warrant the rupture of the unity”. What it suggests is that some denominations are perceived to be outside of the unity of Christian churches who uphold fundamental Christian doctrines. Let’s focus on the main part of your question, “how do Christians determine what is essential?” We need to compare the earliest Christian beliefs with what we have now to establish what is considered “essential”.

The first documented creed on the Christian faith is known as the Apostles’ Creed, written about 150 years after the death of the apostles. It in, we have the fundamental beliefs of Christianity:

• God the Father Almighty, Creator

• Jesus Christ his only Son, our Lord

• Conceived of the Holy Spirit, born of the virgin Mary

• Crucified, died, was buried, resurrected and ascended into heaven

• Sits at the right hand of God the Father Almighty

• Will return to judge the living and the dead

• The Holy Spirit, the Church, forgiveness of sins, resurrection of the body and life everlasting Source: https://www.gotquestions.org/apostles-creed.html

Later, in A.D. 325 comes the Nicene Creed: https://www.gotquestions.org/Nicene-creed.html

Moving on to A.D. 1571 we have the 39 Articles of the Church of England, adopted by Anglicans and Episcopalians. Below are the main doctrines:

• Trinity – Three Persons within the Godhead

• Jesus – the Word or Son of God – from everlasting, begotten, not created

• The Holy Ghost – proceeding from the Father and the Son

• Jesus – died, buried, resurrected, ascended into heaven, and will return to judge humanity

• Sufficiency of Holy Scripture for Salvation

• Of the Nicene Creed and the Apostles Creed

• Of sin, free will, justification (by faith alone), predestination, election and the Church Source: https://www.churchofengland.org/prayer-and-worship/worship-texts-and-resources/book-common-prayer/articles-religion

More recently, we have the basic beliefs of the United Methodist Church which include:

• The Triune God – one God in three persons, Father, Son and Holy Spirit

• The Bible – the inspired word of God

• Sin – all humans are sinners

• Salvation through Jesus Christ

• The Grace of Sanctification

• The Sacraments of Baptism and Holy Communion

• Free will and Social Justice

Source: https://en.wikipedia.org/wiki/United_Methodist_Church#Doctrine

What Christians have in common is based on the Bible, which all Christians believe is the inspired Word of God. Essential to Christian doctrine is the holiness of God, our creator, the eternal relationship between Father, Son and Holy Spirit, and an acceptance that we are all sinners who can only be saved because of what God, in Jesus, has done to pay the price of sin. All Christians believe in the virgin birth, the life, death and resurrection of Jesus and the judgment to come. Through the death and resurrection of Jesus, those who believe in Him can receive forgiveness and be sanctified by the indwelling of the Holy Spirit. They are adopted into God’s family and are spiritually “born again” which results in a transformed life, a life that produces the fruit of the Spirit. Faith in God, in Christ Jesus and the Holy Spirit are foundational to Christianity.

Any denomination that denies the inspiration of Scripture must remain outside the unity of Christianity; likewise, any denomination that denies the sinful condition of humanity, and the need to repent and believe in Christ Jesus as the only way to God. The last word (written before the end of the first century) belongs to Jude:

I felt I had to write and urge you to contend for the faith that was once for all entrusted to the saints. For certain men whose condemnation was written about long ago have secretly slipped in among you. They are godless men, who change the grace of our God into a license for immorality and deny Jesus Christ our only Sovereign and Lord. (Jude verses 3-4; cf. 2 Peter 2:1-3).

Finally, in light of the comment left by Paul Chernoch, I realise that this brief and simple outline is far from complete. No doubt others will be able to add to it and explain it better. It is not my purpose to argue doctrine with others, merely to present some of the “essentials” of Christian unity as you have requested. There is liberty to be experienced with like-minded fellow believers, even though we do not necessarily agree with every point of view. That’s where we exercise charity, to put into practice the love of God that we have received and experienced.