I need the New Testament authority for classes. Where is the doctrine that authorizes classes to be segregated by different ages?
It is common for people seeking to deny biblical authority for some practice to search for only one description and when they can't find it sit back and claim there is no authority. Years ago I remember people arguing that homosexuality was not condemned by God because it wasn't found in the King James Version of the Bible. Yes, in 1611, when the King James Bible was translated, the English language did not have the word "homosexual," but it doesn't mean that the concept wasn't in the Bible. There just wasn't a single word to use, so it had to be described.
If you only look for the phrase "Bible class" in the Bible, you won't find it. But it doesn't mean that the concept isn't there. In Ephesians 4:11-12, we are told that Christ set up various offices to build the church: "And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ." Let me direct your attention to the fact that there exists a position within the church known as "teacher." While all Christians ought to develop the capability to teach, not every Christian can be a teacher. In a list of rhetorical questions, Paul pointed out that no every Christian was a teacher. "And God has appointed these in the church: first apostles, second prophets, third teachers, after that miracles, then gifts of healings, helps, administrations, varieties of tongues. Are all apostles? Are all prophets? Are all teachers? Are all workers of miracles?" (I Corinthians 12:28-29). From the list in Ephesians 4:11 we must also conclude that the duties of a teacher are not the same as an evangelist or a pastor. However, just as you might have an elder (pastor) in a church who is also a preacher, it is possible for an elder or a preacher to also be a teacher. But, those duties don't have to overlap. It is possible to have someone who is a teacher who is not a preacher or an elder.
Now, if someone is designated a teacher, then it follows that there must be students. A teacher without students would be a meaningless position. "Let him who is taught the word share in all good things with him who teaches" (Galatians 6:6). So even though the word "student" is not used in this passage, students are mentioned in the Bible. If a teacher is teaching more than one student at a time, then in English we call that a class.
"And a servant of the Lord must not quarrel but be gentle to all, able to teach, patient, in humility correcting those who are in opposition, if God perhaps will grant them repentance, so that they may know the truth, and that they may come to their senses and escape the snare of the devil, having been taken captive by him to do his will" (II Timothy 2:24-26). Paul says that Christians ought to be able to teach and then proceeds to describe how such teaching should be accomplished. Teaching is not a inborn skill. It is something that must be learned. "For though by this time you ought to be teachers, you need someone to teach you again the first principles of the oracles of God; and you have come to need milk and not solid food" (Hebrews 5:12). New Christians should not be expected to teach, but older Christians ought to develop the ability to teach. Yet, even then, every older Christian will not be qualified to be a teacher. "My brethren, let not many of you become teachers, knowing that we shall receive a stricter judgment" (James 3:1). Not everyone is willing or able to take on the responsibilities of being a teacher. A teacher is responsible to God as to what he teaches. If a person is led into error because of bad teaching, then the teacher will answer to God for both his soul and the souls of his students. It is a heavy responsibility that not every Christian is mature enough to handle.
What has been shown so far is that there is a requirement for churches to have teachers, whose duties are to help build up Christians in the church to maturity. It is not an allowance, but a requirement. However, just as the New Testament does not specify exactly how preaching is to be done, there is no exact requirement for how classes are to be conducted. The method for teachers teaching students is left up to each individual congregation.
We find in the Bible examples of Christians teaching others one-on-one, such as in the teaching of Apollos. "Now a certain Jew named Apollos, born at Alexandria, an eloquent man and mighty in the Scriptures, came to Ephesus. This man had been instructed in the way of the Lord; and being fervent in spirit, he spoke and taught accurately the things of the Lord, though he knew only the baptism of John. So he began to speak boldly in the synagogue. When Aquila and Priscilla heard him, they took him aside and explained to him the way of God more accurately" (Acts 18:24-28).
Teaching could take place privately in Christians' homes as friends from the neighborhood gather around the dining room table. Or teaching could take place in public areas. "And daily in the temple, and in every house, they did not cease teaching and preaching Jesus as the Christ" (Acts 5:42).
It is also possible for a congregation to use a facility they have either rented or purchased in which to teach. Paul spent a period of time teaching in a school. "But when some were hardened and did not believe, but spoke evil of the Way before the multitude, he departed from them and withdrew the disciples, reasoning daily in the school of Tyrannus. And this continued for two years, so that all who dwelt in Asia heard the word of the Lord Jesus, both Jews and Greeks" (Acts 19:9-10).
How a congregation accomplishes its teaching isn't nearly as important as that it does teach both members and non-members. They could use any of the above methods or a combination thereof. Some Christians have gotten into the mind-set that teaching only takes place to bring a person to Christ. But Paul said that all the duties in a church were "for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ; that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, but, speaking the truth in love, may grow up in all things into Him who is the head -- Christ -- from whom the whole body, joined and knit together by what every joint supplies, according to the effective working by which every part does its share, causes growth of the body for the edifying of itself in love" (Ephesians 4:12-16).
Now is teaching the Bible by a congregation limited to only adults? It is true that a child's father is responsible for the child's training. "And you, fathers, do not provoke your children to wrath, but bring them up in the training and admonition of the Lord" (Ephesians 6:4). However, this doesn't imply that only fathers can teach their children. We know that mothers are involved in the teaching process as well (Proverbs 1:8; II Timothy 3:15; II Timothy 1:5). Yet that teaching is not limited to family members. Just a few verses before, Paul addressed the children in the Ephesian congregation. "Children, obey your parents in the Lord, for this is right" (Ephesians 6:1). The apostle John also directed his teaching to children and young people. "I write to you, fathers, because you have known Him who is from the beginning. I write to you, young men, because you have overcome the wicked one. I write to you, little children, because you have known the Father" (I John 2:13). Notice that! Children know God. They have learned some important concepts even though they are small. John called the young men spiritually strong. They didn't get that way by chance. The teaching of God lives within them and they are able to defeat Satan. Hence, we must conclude that a father is responsible for the teaching of his children, but he can take advantage of a variety of teachers to instruct his children in God's word.
If we accept the fact that congregations are to teach God's word through those assigned as teachers and that their students can be members and non-members, young and old, then a congregation can select methods optimal for teaching in its area. An expedience is a chosen method applied to carry out God's will in an efficient manner. The Greek word is sumphero, which is often translated as profitable or helpful. "All things are lawful for me, but all things are not helpful" (I Corinthians 6:12). Just because a righteous task can be accomplished in a certain manner doesn't necessarily mean it is the best manner to be used. Each congregation must look at its situation and determine what is the most helpful method for accomplishing its duty of teaching.
Many congregations in United States have selected having classes on Sundays near the time of their worship services because it is convenient to hold classes while everyone is gathered. Most also schedule formal classes during the mid-week because they know that one hour a week is not enough time to get lessons across. Why divide by ages? Because the lessons a child needs and the lessons a child can grasp are not the same lessons a young person needs or can understand. In turn those lessons are not the ones needed by older adults. I know of no passage that requires that everything a congregation does must be done by the entire congregation together. There are some things that do require all the congregation, such as our worship (see I Corinthians 11). But does that mean everything is done together? When a congregation supports a preacher, does that mean he can only speak when the entire congregation is present? Obviously not. When a congregation designates some to be teachers, can their work only be done with the entire congregation? Again, I would say obviously not.
Bible classes are not the only way for a congregation to accomplish its duty to have teachers teaching God's word, but it is a way that works in many areas. When someone argues against Bible classes, I'm inclined to ask who are their teachers and how do they fulfill their roles as teachers. I know that this congregation works hard through its teachers.