Very long and quite complex genitive absolute here:
19 παντος ακουοντος τον λογον της βασιλειας και μη συνιεντος ερχεται ο πονηρος και αρπαζει το εσπαρμενον εν τη καρδια αυτου, ουτος εστιν ο παρα την οδον σπαρεις.
19 When anyone hears the word about the kingdom and does not understand it, the evil one a comes and snatches what was sown in his heart; b this is the seed sown along the path.
Adj – pcpl – art + dir obj – art + gen modifier – conj – negated pcpl
Whole clause is built around the genitive particle and is independent of the main clause (which is shown underlined).