Matthew 1:2

ἐγέννησεν. In accordance with all the uncial MSS. the final ν (called ἐφελκυστικόν or ‘attached’) is added in the best critical editions before vowels and consonants alike. To this rule Tischendorf admits a few exceptions, as δυσί (ch. Matthew 6:24), βαστάσασι (ch. Matthew 20:12). It is probable that ‘ν’ ἐφελκυστικόν appeared invariably in the written prose language even in Attic Greek. See Winer, 43, 44, note 2, and Scrivener’s Introd. p. 486, 487.

2. τὸν Ἰσαάκ. The article is generally used with indeclinable proper names for the sake of perspicuity. See Winer, p. 141.