Psalm 20:6 (ESV)

6 Now I know that the LORD saves his anointed; he will answer him from his holy heaven with the saving might of his right hand.

Obtaining the victory is already somewhat prepared for in the previous verse (Psalm 20:5), because it already mentioned the victory (i.e., salvation). Furthermore, the first-person speaker takes the floor in this verse and says that the Lord answers by saving his anointed. Do note that it does not say the king, but his anointed. Through the possessive his and the word anointed, it becomes clear that the king is God’s office-bearer, because one who was called to a certain position was anointed.

Now, looking at the history of Israel, it often happened that the Lord granted victory, especially during the reigns of David and Solomon. But it did not always work out that way, for example, the pious King Josiah died in a war with Pharaoh Neco of Egypt (see 2 Kings 23:29–30). Therefore, this verse is only completely true when it concerns Christ the King (the Anointed). In other words, this verse (and with that the whole psalm) is fulfilled in Jesus Christ. His tremendous victory over Satan, sin, and death is written about in various places in the New Testament (see e.g., Luke 24:51, Acts 2:33, and Philippians 2:9–11). In King Jesus, Psalm 20:6 has been completely fulfilled. Christians are celebrating this victory every week, usually on the first day of the week. Therefore, Psalm 20 is a good Psalm with which to begin the worship service.