Charles Spurgeon Commentary Mark 4:14-15

"The sower soweth the word. And these are they by the way side, where the word is sown; and when they have heard, straightway cometh Satan, and taketh away the word which hath been sown in them." — Mark 4:14-15 (ASV)

There is always a bird where there is a seed lying on the road, and there is always a devil where there is a sermon heard, but not received into the heart. Satan cometh immediately. He is very prompt; we may delay, but the devil never does: When they have heard, Satan cometh immediately, and taketh away the word that was sown in their hearts.