Psalm 2
Seeing as Psalm 2:1–12 is quoted in the prayer of the believers, it makes sense to sing from this psalm. It can be sung perhaps at the beginning of the service or just before your Scripture reading.
Psalm 46
In Psalm 46:1–11 we confess that the Lord will help his church, that we can trust him even if the world around us should fall apart.
13 Now when they saw the boldness of Peter and John, and perceived that they were uneducated, common men, they were astonished. And they recognized that they had been with Jesus.