He who loves his brother. Now at last the contents of the great commandment are explicitly mentioned. Brotherly love is an important theme in this Letter; see also 3.11-18, 23; 4.7, 11, 20-21; 5.1-2. In the controversy with the false teachers, it is the test for people’s fellowship with God. The term always implies activity, doing deeds of love.
† John often uses the verb “to love” in his Letters. In most occurrences both the agent and the goal are personal, and the reference is to men loving God (4.10, 20-21; 5.2) or to men loving men, namely, their brother(s) (2.10; 3.10, 14; 4.20-21), one another (3.11, 23; 4.7, 11-12; 2 John 5), “the parent” and “the child” (5.1), “the children of God” (5.2), “the elect lady” (2 John 1), “Gaius” (3 John 1). In three occurrences the agent is God, loving man (4.10-11, 19), and in two a personal goal, though not expressed, can be inferred from the context (3.18; 4.19). Finally in one passage the goal is nonpersonal, namely “the world” (2.15). For problems of rendering this verb, see comments on the noun in 1 John 2.5.
Abides in the light, or ‘is-and-remains in the light,’ ‘dwells/lives in radiance and goes on dwelling/living in it (or goes on doing so)’ “stays in the light” (Good News Translation).
† For “to abide in” see comments on 1 John 2.6, group (c). The verb has a nonpersonal goal here. The same is found in “to abide in love,” or ‘to love and go on loving’ (4.16, second occurrence); “to abide in the doctrine,” or ‘to keep to (or obey) the doctrine, and go on keeping to it (or obeying it, or doing so)’ (2 John 9). Compare also “to remain (same verb in the Greek) in death,” in 3.14.
In it there is no cause for stumbling. The Greek words that Revised Standard Version renders as in it (that is, in the light), may also mean “in him” (that is, in him who loves). The second interpretation is preferable, because comparable expressions are used with a personal reference in 1.8 and 10 (“in us”); 2.4-5 (“in him”), 2.8 (“in him and in you”). Then the meaning of the present verse is either “there is nothing in him to make others stumble” or “there is nothing in him to make him stumble himself.” Both are possible, and the expression is more frequently used in the former meaning (compare, for example, Rom 14.13; 1 Cor 8.13). Yet here the latter meaning seems to be more likely because of verse 11, which also treats of the consequences to the person concerned himself, not to others. Accordingly the clause may be rendered ‘he has no reason to stumble,’ “there is nothing to make him stumble” (New English Bible), ‘he does not stumble over anything.’
Cause for stumbling (in the Greek literally “trap,” “snare”) is used metaphorically for what causes a person to err or to sin. Some renderings used are, ‘in what one’s foot gets entangled’ (said with reference to a hunter in the jungle), ‘what-leads-astray,’ ‘what causes one to fall.’ In other languages one says, ‘what entices to evil,’ ‘what becomes cause to sin,’ ‘what causes to become evil.’
If the present verse is interpreted as indicated above, such renderings of cause for stumbling may result in, ‘there is nothing in which his foot will get entangled,’ ‘he will not fall because of anything,’ ‘nothing will entice him to evil,’ etc.
Quoted with permission from Haas, C., de Jonge, M. and Swellengrebel, J.L. A Handbook on The First Letter of John. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .