Once again, the praise of Zion is sung. She is the city of God.
That is its unique glory. Significantly, it contains a form of the Hebrew verb "כבד" (ESV: glory). This emphasizes above all that these are weighty, extremely important matters. It is about things that are beyond human understanding, that are wonderful in our eyes. It is also about delightful things. It is obvious to see the effect of this in the continuation of this Psalm. When God is going to speak, something is about to happen. Then we, as humans, can expect a lot.
The meaning of the Hebrew word "סֶֽלָה," (ESV: Selah) is uncertain. It can be a music indicator or a pause sign. Some think that it places emphasis on the foregoing. That could well be the case. This is also possible in Psalm 87:6.
3 Glorious things of you are spoken, O city of God. Selah