Look to yourselves, or “watch yourselves” (Good News Translation), ‘take care,’ ‘be on your guard,’ ‘walk with thought.’ This and similar expressions are often used in warnings in connection with the Last Hour; compare a passage like Mark 13.5.

That you may not lose what …: this dependent clause is in some cases better rendered as a coordinated sentence; for example, ‘look to yourselves; if you don’t do so (or if not, or otherwise), you will lose what…,’ ‘be on your guard; don’t lose what….’

To lose is used here with reference to good things they had obtained and has the sense of ‘to find missing,’ ‘to suffer the loss of’; or more actively, ‘to destroy.’ In some cases a shift to an intransitive construction is preferable, as in ‘take care that what … may not disappear (or be without results, or be in vain).’

What you have worked for, preferably “what you have accomplished,” ‘the work you have done,’ referring to work done by the readers in the congregation and in mission.

There is a variant reading of the Greek text, in which the verb is in the first person plural instead of in the second person. It is not easy to decide between the two. If the first person is accepted as the original reading (as done among others by Nestle, New English Bible, Bible de Jérusalem, Luther 1984), it should be taken as referring to John and his helpers and, therefore, having exclusive force.

Similar variant readings are given for the preceding verb, “to lose,” and the following verb, “to win,” but the chances that the first person is the original reading are less in these two cases than in the phrase under discussion.

But (that you) may win a full reward: this and the preceding clause form an antithetical pair, which states virtually the same thing, first in a negative, next in a positive construction. If the preceding clause has been restructured, it is preferable for the present one to follow the same structure.

To win a full reward, or to ‘obtain/receive/be-given a full reward,’ is a standing Jewish expression (compare, for example, Ruth 2.12 in the Greek version of the Old Testament). In the New Testament this and similar expressions are used in connection with eschatological expectations; compare Matt 5.12; Mark 9.41; 1 Cor 3.8, 14; Rev 11.18; 22.12.

A full reward, or ‘your full/whole/complete reward’: the adjective is sometimes better rendered as an adverbial qualification; for example, ‘win your reward in full (or completely, or without anything lacking).’ The noun indicates what one receives because of the work one has done. Here it probably refers to the eternal life the believers receive from God because they obey his commandments and follow Jesus.

Some versions can render reward simply by the common term for “wages,” such as, ‘your-work-its-price.’ In others one can better use renderings like ‘all God promised to grant you,’ ‘all (the benefit) which God wants to give you,’ ‘all that which God has prepared for you.’

Quoted with permission from Haas, C., de Jonge, M. and Swellengrebel, J.L. A Handbook on The Second Letter of John. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .