{Is this} (estin de haut(885c)). Means this. Jesus now proceeds
to interpret his own parable. {The seed is the word of God} (ho
sporos estin ho logos tou theou). The article with both subject
and predicate as here means that they are interchangeable and can
be turned round: The word of God is the seed. The phrase "the
word of God" does not appear in Matthew and only once in Mark
( Mr 7:13 ) and John ( Joh 10:35 ), but four times in Luke ( 5:1  8:11,21  11:28 ) and twelve times in Acts. In  Mr 4:14  we have
only "the word." In  Mr 3:31  we have "the will of God," and in
 Mt 12:46  "the will of my Father" where  Lu 8:21  has "the word
of God." This seems to show that Luke has the subjective genitive
here and means the word that comes from God.