1 Thessalonians 4:9

Concerning love of the brethren

(περ της φιλαδελφιας). Late word, love of brothers or sisters. In profane Greek (one papyrus example) and LXX the word means love of those actually kin by blood, but in the N.T. it is the kinship in the love of Christ as here.Are taught by God

(θεοδιδακτο εστε). Only here and ecclesiastical writers. Passive verbal adjective in -τος from διδασκω as if θεο- in ablative case like διδακτο θεου (John 6:45).To love one another

(εις το αγαπαιν αλληλους). Another example of εις το and the infinitive. Only those taught of God keep on loving one another, love neighbours and even enemies as Jesus taught (Matthew 5:44). Note the use of αγαπαω, not φιλεω.