This psalm is particularly about the character of the wicked. What a description there is! In the latter part of verse 4, the marginal reading is better than the text: "All his thoughts are, there is no God." He says in his heart, "God hath forgotten; He hideth His face; He will never see it," but in this he is very much mistaken, for God will arise in answer to the cry of His oppressed and suffering people of that day.
Verses 16-18 celebrate God's (the Lord's) coming in to deliver His own, and to put down the oppressors.
It is well known from Scripture that there will be in the last days a man who is called the Antichrist, the fierce enemy of the godly Jews; these Psalms tell of the time when he will be ruling in Jerusalem. In Psalm 9:55Thou hast rebuked the heathen, thou hast destroyed the wicked, thou hast put out their name for ever and ever. (Psalm 9:5) "the wicked" is one person, not many, it is evidently the Antichrist.
Psalm 9 shows the regard God has and will have, for those who are humble and seek Him; while Psalm 10 shows how differently He looks at the wicked.