Genesis 3:14
13 So the Lord God said to the woman, “What is this you have done?” And the woman replied, “The serpent tricked me, and I ate.” 14 The Lord God said to the serpent, “Because you have done this, cursed are you above all the cattle and all the living creatures of the field! On your belly you will crawl and dust you will eat all the days of your life. 15 And I will put hostility between you and the woman and between your offspring and her offspring; he will strike your head, and you will strike his heel.”
1 Samuel 17:49
48 The Philistine drew steadily closer to David to attack him, while David quickly ran toward the battle line to attack the Philistine. 49 David reached his hand into the bag and took out a stone. He slung it, striking the Philistine on the forehead. The stone sank deeply into his forehead, and he fell down with his face to the ground. 50 David prevailed over the Philistine with just the sling and the stone. He struck down the Philistine and killed him. David did not even have a sword in his hand.
Notes and References
"... Goliath may have fallen for another reason. When Goliath fell facedown, this may allude to the serpent eating the dust of the earth (Genesis 3:14). Both Rabbah Leviticus and Rabbah Song of Songs state that Goliath fell facedown so that his “mouth that taunted and blasphemed be put in the dust, as it is written, ‘Hide them in the dust together, bind their faces in the hidden place’.” Though both of these midrashim connect Goliath’s fall to eating dust, they do not cite Genesis 3:14 but rather Job 40:13. Still, previous interpreters have linked Goliath falling facedown to God putting his adversaries face in the dust. Not only did David cause Goliath to fall down, but he also decapitated Goliath. David killed Goliath not with the stone but by removing his head (1 Samuel 17:46, 51; ראשׁ). Leithart captures the significance of this: “Goliath was dressed like a serpent with his scale armor, and he died like a serpent, with a head wound, just as the Philistine god Dagon had his head crushed.” As God promised that the serpent would eat the dust (Genesis 3:14) and have his head bruised (verse 15), so too David made Goliath fall facedown (i.e., eat the dust; 1 Samuel 17:49), and then he delivered a mortal blow to Goliath’s head (verse 51) ..."
Verrett, Brian A. The Serpent in Samuel: A Messianic Motif (p. 157) Resource Publications, 2020