Let me introduce this subject by citing some appropriate words from Gordon Wenham relating to Numbers 3:40-51: “In the principle that the servant Levites redeem the first-born Israelites, Christians may see an anticipation of Jesus the great suffering servant who redeemed his people. This chapter's insistence that the Levites must prevent other Israelites from sinning by warning and, if necessary, killing encroachers anticipates New Testament challenges, particularly to elders to correct erring brethren.” Some examples of this latter duty are seen in Exodus 32:25-28 and Numbers 1:47-54. Wenham then lists a number of NT passages, all of which are given below with comments from various scholars. You will note that in these comments, I have purposely limited myself to those citations which help spell out both the real continuities and discontinuities of the NT teachings with those in the Old Testament.
Matthew 18:15ff “Matt 18:15-18 forms the well-known passage in church discipline. Here a procedure is outlined not just for confronting flagrant sinners, but for dealing with unresolved grievances...and if the sinner still refuses to change, then the church must proceed with putting that person out of fellowship (18:17b)...This punishment resembles the OT practice of cutting a person off from Israel's assembly (see, e.g. Gen. 17:4; Exod. 12:15,19; 30:33-38).” (Blomberg)
Acts 18:25-26 Marshall says in regard to these verses, “The 'way of the Lord' is OT language for the kind of conduct that the Lord requires of his people and hence for the teaching that describes it (Exod. 32:8; Deut. 5:33).”
Galatians 2:11ff Donald Guthrie says that “the food laws of Judaism were stringent, based on Levitical law. Segregation from Gentiles while eating was not because of any personal animosity toward the individual Gentiles concerned, but because of the fear of contamination by eating food forbidden under the law. It was, therefore, an essentially protective measure...But Christian liberty and fellowship were never intended to be shackled by ancient taboos...Peter's fear of the circumcision party seems to have outweighed entirely any consideration he may have had for the Gentile brethren...This is fitting reminder that Christian leadership always involves responsibility toward others...Paul considered a public remonstrance was essential, because of the basic principles involved.”
Galatians 6:1 Martyn: “Even though the reference ['a transgression of some sort'] is general – one might wonder how Paul thinks the Galatians will identify a specific transgression now they are no longer 'under the authority of the law' (5:18...). First he has already specified for them a list of representative effects of the Flesh. Now he emphasizes elements on that list that destroy community, such as a tendency constantly to compare oneself with others. Moreover, Paul thinks that the Spirit that builds community will provide criteria for identifying transgressions that destroy community.”
As to those who commit such transgressions, Martyn says, “The restoration, then, is to be completely devoid of lasting stigma. It is to be carried out with the gentleness that is one of the marks of the Spirit-led community...and also with circumspection. For as the next clause indicates, all are subject to missteps.”
1 Thessalonians 5:12-14
A few of Paul's many admonitions in these verses can be traced back to Old Testament teachings. For example, Malherbe states: “Paul's use of makrothymeisthe ('be patient') is influenced by Jewish usage. An insignificant word in nonbiblical Greek, it takes on a profound significance in the LXX [i.e. Greek Septuagint], where it describes God's relationship with his people. The basic passage in Exod 34:6 ('The Lord God, compassionate and merciful, patient [makrothymos] and full of pity')...becomes a refrain in later Jewish literature (e.g., Ps 102:8; Joel 2:13). In the Wisdom literature, it is also a quality of the wise man (Prov 16:32; 17:17; Sir 5:11).”
And regarding the phrase “encourage the fainthearted” in 5:14, Elias says, “Both encouragement and consolation may be included in this ministry. Again the problem comes at the point of determining the nature of the needs within this particular group. This word (literally, the small souled or simply the little people) appears nowhere else in the NT, but in the Septuagint it characterizes fearful or grieving people (Prov. 18:14; Isa. 35:4; 54:6)...Such people, the faint hearted, need the comfort of brothers and sisters who have caught on that, through Jesus' death and resurrection, believers can face both life and death with hope and joy (4:13-18; 5:10).”
I Timothy 5:19-20 “Probably as a result of heresy and its influence on some of the church leadership, Paul addresses the issue of due process in the examination and (if necessary) discipline of elders...Paul again draws on Mosaic legislation with a long history of acceptance in Judaism and in the church to ensure that due process is followed.” (Towner)
James 5:19-20 “It is debatable whether these verses refer to the restoration of a truly regenerate person or the conversion of an unregenerate one...Some have understood 'death' as a loss of communion or physical death (cf. 1C. 11:30), and there is no evidence that physical death was the regular punishment for backsliding.” (Carson) He goes on to explain that “the phrase 'cover a multitude of sins' in v. 20 “is evidently an allusion to Prov. 10:12, which is quoted more fully, but not exactly, in I Pet. 4:8...The meaning is that 'the soul is not merely saved out of death, not merely rescued from peril, but blessed, Ps. 32:1' (Knowling).”