This little paragraph seems to come in rather abruptly, with no connection with what precedes. As a result, Oesterley regards it as "a fragment of a larger piece" which James here tears from its context, perhaps a saying from Jesus. But Plummer is more likely correct in thinking of it as an appendix after rounding out the epistle, coming back to the blessedness of trial, with which topic the epistle opens.
The exhortations need not have a close connection with each other. As a matter of fact, James has spoken more against the sins of speech than any other single sin. Plummer well says, "He has spoken against talkativeness, unrestrained speaking, love of correcting others, railing, cursing, boasting, murmuring" (see 1:19, 26; 3:1-12; 4:11, 13; 5:9). He now recurs to the sins of speech to say a few words against one of the commonest evils of which he has not spoken specifically. He evidently is thinking of the words of Jesus as we have them in Matthew 5:34-37, though it is not an exact quotation.[94] He may, indeed, as Resch holds, give another version of the same logion (cf. 2 Cor. 1:17). But there was ample ground for this prohibition, as the Jews had learned how to split hairs on the subject of profanity.
The Third Commandment was plain enough on the subject, and it was supported by the Pharisees and the Essenes. The Essenes, indeed, opposed all oaths, even before courts, and were said to have been excused by Herod from taking the oath of allegiance (Jos., _Ant._ xv. 10.4). And yet, as Mayor notes, this is not consistent with the oath of initiation which the Essenes took (Jos., _War_ ii. 8.7). The Jewish view is well represented by Sirach 23:7-11 and by Philo (M. 2, p. 184).
The early Christians found trouble with this verse of James, as with the words of Jesus on the same point. See the list of quotations from the early writers in Mayor. Augustine sees no harm in oaths before courts if it were not for the danger of committing perjury. And yet it may be seriously questioned if Jesus or James is thinking of oaths in courts of justice, since Jesus himself did not refuse to answer when put on oath by the high priest before the Sanhedrin (Matt. 26: 63 f.). Besides, solemn asseveration is allowed in the Old Testament (Deut. 6:13; 10:20; Isa. 65:16). It is far more likely the flippant use of oaths (profanity) that is here condemned. There were, and are still, all sorts of devices by which more or less pious people feel justified in calling on the name of the Lord in ordinary speech. It is today one of the saddest things in life to note how common profanity is in the ordinary speech of men and of boys, mannish boys who imitate the men about them. It is positively disheartening to hear it on the streets, in the streetcars, in the trains.