When anyone hears the message of the kingdom but does not understand it, the evil one [i.e., the devil] comes to him and grabs away what had been sown in his heart. This is the person who was scattered to the side of the road.
And those people [represented by the seed falling] along side of the road are those who have heard the word [of God], but the devil comes and takes away the word from their heart, so that they do not believe it and receive salvation.
Therefore, you should put away [from you] all moral filth and overflowing wickedness and humbly receive the word [of God], planted within you [by the Holy Spirit. See John 16:8], which is capable of saving your souls.