God's People Rejoice In The Security Of The City Of God Now Evidenced Not Just By Hearsay But Also By What They Had Themselves Seen (Psalms 48:8).
‘As we have heard, so have we seen,
In the city of YHWH of hosts,
In the city of our God,
God will establish it for ever. [Selah
The deliverance having taken place, and the enemy having faded away, God's people triumphantly declare that they have now seen with their own eyes the delivering power of God revealed on behalf of His people. They had from their past heard many stories of His delivering power, but now they had seen it for themselves. It was thus clear to them that the city of YHWH of hosts, the city of their God, would be established by Him for ever.
And while they were faithful to Him that was, of course, true. But what they later forgot was that their security depended on faithfulness to the covenant. The truth was that God's promises were only secure to an obedient people. That is why Jerusalem would end up a ruin, not once but a number of times (under Nebuchadnezzar, under Antiochus Epiphanes and under the Romans). However, in all that it was not that God had forgotten His true people. While unbelieving Israel suffered and perished, His true people, the remnant who expanded into the church, were preserved through all the tribulations that would come, as part of the whole people of God who will rise again at the last day (Isaiah 26:19). Their names were recorded in Heaven. Thus God's cause was secure. It is the outward trimmings that suffer, as they would later also for the churches in Asia Minor to whom John sent his letters (Revelation 1-3), when their lamp became but a dim glow through the rise of Islam. But the inner heart of His true people will burn on for ever.
‘Selah.' This once again indicates a musical break and a pause for thought.