An enemy in the Bible refers to people who are in the love of evil and the false thinking that springs from evil. On a deeper level it refers to the forces of hell itself, and on an abstract level it refers to evil itself and falsity itself – which are, obviously, the ultimate enemies we have to fight.

(Odkazy: Apocalypse Explained 671; Arcana Coelestia 2851 [1-15], 8282, 8289, 9255 [1-2], 9313)

9255. 'When you meet your enemy's ox or his ass going astray' means unauthentic good and unauthentic truth with those who are outside the Church. This is clear from the meaning of 'enemy' as those outside the Church, who are the subject below; from the meaning of 'ox' as the external man's good, and from the meaning of 'ass' as the external man's truth, both dealt with in 2781, 9135 - but unauthentic good and truth, such as exists with those outside the Church, who are meant by 'enemy'. The reason why those outside the Church are meant by 'enemy' is that they have a different idea of what the good and truth of faith are, because they do not possess the Word and therefore do not know anything about the Lord or about Christian faith and charity that come from the Lord alone. Consequently their truth of faith is not authentic, neither is their good of charity. Therefore also they do not live together in the next life with those who belong to the Church but are separated from them. All in the next life are formed into communities according to their good and the truth flowing from it, for these are what compose spiritual life and link people together.

[2] However, those in heaven do not regard people outside the Church as enemies; rather they teach them and bring them to Christian good, which is also welcomed by those of them who in the world have led dutiful and obedient lives, in some kind of charity towards one another that is prescribed by their religion. But the sense of the letter of the Word calls them 'enemies' on account of their lack of spiritual agreement, which is, as has been stated, their different idea of what the truth of faith and the good of charity are. See what has been shown from experience regarding the state and condition in the next life of nations outside the Church, in 2589-2604, 2861, 2863, 4190, 4197. The requirement to regard these very people as friends, and to teach and correct them, is the meaning in the internal sense of the words you shall surely bring it back, which the next paragraph deals with.

[3] Only this needs to be added here, that in the Word various kinds of beasts mean affections and inclinations such as the human being shares in common with beasts, and in the spiritual sense affections for goodness and truth, internal and external, see 45, 46, 142, 143, 246, 714, 715, 776, 2179, 2180, 2781, 3218, 3519, 5198, 9090; and that beasts were therefore used in sacrifices in accordance with their spiritual meaning, 1823, 2180, 2805, 2807, 2830, 3519. Consequently this law of personal conduct stating that an enemy's oxen and asses going astray should be brought back to him means in the spiritual sense such things as are characteristic of the Church, thus such as are feelings of mutual love or charity towards those whose ideas are different from the Church's truths.