Shared ground
Paul addresses two needs at once in 2 Thessalonians 3:13–15: steady perseverance among those who are doing good, and a firm, measured response to someone who refuses the instruction carried “by this letter.” The text is explicit that weariness is a real danger (v.13), and that disobedience here is defined by rejecting the letter’s instruction (v.14).
The passage also holds together two realities that can seem in tension. There is a real boundary (“have no company with him,” v.14), and there is also a real continuing relationship (“do not count him as an enemy…as a brother,” v.15). The stated aim of the boundary is correction—so that the person becomes ashamed—not retaliation or rejection.
Where interpretation differs (only where needed)
One main question is how strict “have no company with him” is. Some read it as near-total social avoidance, including shared meals, to create clear social pressure. Others read it as limited association: continuing basic interaction and counsel, while withholding normal, comfortable fellowship that would signal approval.
A second question is what “ashamed” means in practice. Some take it mainly as an inward moral awakening (the person recognizes their wrong). Others think it likely includes some public dimension, since the church’s “noting” of the person and reduced association would be visible.
A third question is who is responsible to “admonish.” Some infer a more organized process led by recognized leaders. Others infer that the whole community participates, since the instructions are addressed broadly (“brothers”) and involve communal patterns of association.
Why the disagreement exists
Paul gives clear goals and limits, but fewer procedural details. The phrases “note that man” and “no company” can describe a range of social actions, and first-century house-church life (shared meals, mutual support) makes the practical meaning more complex than a simple modern category.
What this passage clearly contributes
Explicitly, the passage adds that perseverance in doing good should continue even when others undermine it (v.13). It also establishes that refusing apostolic instruction delivered in the letter is serious enough to require a communal response (v.14). At the same time, it places a boundary on the community’s posture: the person is not treated as an enemy, but warned within a “brother” relationship category (v.15). The overall shape is discipline-with-restoration: clear identification, reduced close association, and continued corrective speech, aimed at bringing the person to recognition and change rather than cutting them off as hostile outsiders.