Praise ye the Lord. Sing unto the Lord a new song, and his praise in the congregation of saints.
2 Let Israel rejoice in him that made him: let the children of Zion be joyful in their King.
3 Let them praise his name in the dance: let them sing praises unto him with the timbrel and harp.
4 For the Lord taketh pleasure in his people: he will beautify the meek with salvation.
5 Let the saints be joyful in glory: let them sing aloud upon their beds.
6 Let the high praises of God be in their mouth, and a two-edged sword in their hand;
7 To execute vengeance upon the heathen, and punishments upon the people;
8 To bind their kings with chains, and their nobles with fetters of iron;
9 To execute upon them the judgment written: this honour have all his saints. Praise ye the Lord.
One might wonder, after reading this Psalm, what the first part (praising God, singing a new song to Him, rejoicing in Him with music and dance) has to do with the second part (vengeance, double-edged swords, taking captives and punishment). The two parts don’t seem to fit together in the same Psalm.
And yet, we had a situation like this in Nehemiah’s day (Nehemiah 4:17-18), when Sanballat and his allies wanted to prevent the rebuilding of the wall of Jerusalem. The men rebuilding the wall did so with work tool in one hand and weapon in the other-- praising God for the re-building of the wall and fighting off the enemy at the same time.
There may be times in your life where you praise God on the one hand and on the other hand you are under attack by the enemy. This may seem contradictory, but the more we reflect God's character and praise Him with our lives – the more the enemy of souls wants to attack us. We praise God for the victory that is already won and at the same time put on the whole armor of God (Ephesians 6: 10-17) to fight the enemy.