Sound Doctrine:

 

“ For I have not shunned to declare unto you all the counsel of God.” 
(Acts 20:27)

“Holding fast the faithful word as he hath been taught, that he may be able by sound doctrine both to exhort and to convince the gainsayers.”.
 (Titus 1:9 )  

"The Price Of a Testimony For "All The Counsel Of God”: “ Buy the truth, and sell it not; ...” (Pr.23:23)

The Church of the Lord Jesus Christ is called:

1) To preach the Gospel in Its purity, in accordance with the Holy Scriptures.
2) To confirm the Brethren, teaching them to observe all things the Lord commanded, without omitting or diminishing any of His instructions.
3) To defend the Gospel from the attacks trying to deny it, distort it or diminish it.

With this regard see:

The Price of the Testimony for “All the Counsel of God”: “Buy the truth, and sell it not” (Pr. 23:23). This is a call to keep all the Counsel of God. Doctrinal synthesis of the Church of Ephesus.
Biblical Synthesis of purposes, doctrine and practices of the Church: Constitutional basis of churches according to the New Testament.
Doctrinal Synthesis: A synthesis of the doctrinal basis of Christian faith in accordance with the authorized source, which is the Holy Bible, the Word of God.
Summary of Doctrines included in “all the counsel of God”
The Doctrine of God. The One and Triune God.
The Holy Scriptures.
The Angels.
The Creation; the Sin and its Due Punishment.
Salvation.
Justification and Reconciliation.
Regeneration.
Adoption.
Sanctification.
Good Works.
Future Life.
Death and the Intermediate State.
The Blessed Hope of the Believer: The Bodily Advent of the Lord Jesus Christ or the Second Coming of The Lord.
The Events after the Millenarian
The Second Resurrection and the Final Judgement.
New Heavens and New Earth.
The Church
The Baptism.
The Lord’s Supper.
Biblical Doctrine of Separation.
Biblical Doctrine of Unity.
Doctrinal Declaration:

The churches of the testimony declare that the Holy Scripture is their only rule of faith, doctrine and practice. As a brief statement -among other truths equally Scriptural- they unanimously express that belief in the doctrines that gave rise to their protest and which are the same as those believed and practised by faithful Evangelical Christians throughout the centuries. 

1) The Bible is the Word of God, inerrant and infallible, inspired by the Holy Spirit to those who wrote it and who where kept from all error.

2) We worship the only eternal and true God, One in essence and Triune in person: Father, Son and Holy Spirit; Creator and Sus­tainer of all things visible and invisible.

3) The Lord Jesus Christ is the only Saviour and Mediator between God and man. We confess His Deity; His true and genuine huma­nity; His virgin birth; His sinless life, the redemption from our sins by His blood in His atoning and vicarious death; His bodily re­surrection; His ascension to glory; His promised return in the air to snatch away His own before the Great Tribulation, resurrecting the dead and transforming the living, so as to constitute His Judgement Seat of recompense and celebrate the marriage feast of the Lamb; His return to the earth with His saints to establish His millennial reign; the resurrection and final judgement; new heavens and new earth.

4) Salvation by grace alone, not by works, received through repentance toward God and faith toward our Lord Jesus Christ. The eternal bliss of the saved and the eternal punishment of the lost.

5) The present personal work of the Holy Spirit, the only vicar of Christ on earth Whom He glorifies in forming the Church, begett­ing, sanctifying, endowing and fructifying the believers spiritually.

6) The Church is the body of Christ, Who is the foundation, Head, Lord, only High Priest and Bridegroom.
The pillar and ground of the truth.
Its primary purposes are: to preach, defend and confirm the Gospel.
Its form of government is Theocratic - Biblical - Congregational.
Its ordinances are: baptism by immersion of believers and the me­morial of the Lord's supper.
Its nature is: a spiritual home, not denominational or sectarian; whether considered as a General Assembly (Matt. 16:18), or as a local church, each is fully autonomous (Phil. 1:1; Philem. 1,2).

7) The real spiritual union of born-again believers and their calling to the unity of the faith in doctrine and practice as a manifestation of complete fraternal fellowship.