What does Psalm 55:20 mean?

In this psalm, David expressed intense fear in the face of danger (Psalm 55:2–8). This came along with the betrayal of a former ally (Psalm 55:12–13). This seems to fit the rebellion of David's son, Absalom, who forced David to retreat from Jerusalem (2 Samuel 15:14), and was aided by Ahithophel, one of David's advisors (2 Samuel 15:31). Despite fear, David trusts that the Lord will rescue him (Psalm 55:16–18).

Here, David singles out the traitor among his enemies. He describes this person as attacking his friends and breaking his promises. This would apply appropriately to Ahithophel, who at one time was a trusted advisor to the king (2 Samuel 15:12; 16:23). Scholars suspect Ahithophel might have been motivated by revenge; he may have been the grandfather of Bathsheba, the woman taken by David in a murderous cover-up (2 Samuel 11:3; 15:12; 23:34).

Judas Iscariot traveled with Jesus for years, giving every appearance of being Jesus' friend. The other disciples must have assumed he could be trusted. He was the group's treasurer, but he violated their trust. John 12:6 reveals "he was a thief, and having charge of the moneybag he used to help himself to what was put into it." His love of money seems to have been a motivating factor in his betrayal of Jesus (Matthew 26:14–16); he received thirty pieces of silver for turning Jesus over to the chief priests, which he later attempted to return (Matthew 27:3). He expressed remorse, but not repentance (Matthew 27:4), and he took his own life (Matthew 27:5). The presumed traitor mentioned in this psalm, Ahithophel, also committed suicide (2 Samuel 17:23).