[4:10] 1 tn Once again there is the (by now familiar) problem of determining whether the referent of this phrase (1) precedes or (2) follows. Here there are two ὅτι (Joti) clauses which follow, both of which are epexegetical to the phrase ἐν τούτῳ (en toutw) and explain what the love of God consists of: first, stated negatively, “not that we have loved God,” and then positively, “but that he loved us and sent his Son to be the atoning sacrifice for our sins.”
[4:10] sn What is important (as far as the author is concerned) is not whether we love God (or say that we love God – a claim of the opponents is probably behind this), but that God has loved us and sent his Son to be the atoning sacrifice which removes believers’ sins. This latter point is similar to the point made in 2:2 and is at the heart of the author’s dispute with the opponents, because they were denying any salvific value to Jesus’ earthly life and ministry, including his death on the cross.
[4:10] 3 sn As explained at 2:2, inherent in the meaning of the word translated atoning sacrifice (ἱλασμός, Jilasmos) is the idea of turning away the divine wrath, so that “propitiation” is the closest English equivalent. God’s love for us is expressed in his sending his Son to be the propitiation (the propitiatory sacrifice) for our sins on the cross. This is an indirect way for the author to allude to one of the main points of his controversy with the opponents: the significance for believers’ salvation of Jesus’ earthly life and ministry, including especially his sacrificial death on the cross. The contemporary English “atoning sacrifice” communicates this idea more effectively.
[4:19] 4 sn No object is supplied for the verb love (the author with his propensity for obscurity has left it to the readers to supply the object). The obvious objects that could be supplied from the context are either God himself or other believers (the brethren). It may well be that the author has both in mind at this point; the statement is general enough to cover both alternatives, although the following verse puts more emphasis on love for the brethren.