Who is he, this King of glory?
The LORD Almighty— he is the King of glory. Selah
The Hebrew Selah is one of those words that cannot be easily translated or understood in modern language. Because of its placement in Psalms and Habakkuk, most scholars understand it to be some kind of musical notation. Most agree that it means a rest, or a quiet moment, before moving forward. Some scholars, however, give it more importance. They say that the word is similar to another word that means "to weigh," but with the idea that Selah follows text that should be weighed or considered carefully.
In either case, Selah is a reminder to be still for a moment, even in the midst of great praise and adoration. The psalmists exhort God's worshippers to sing, make music, shout, dance, clap, and create a number of other joyful noises. In times of great happiness and in times of great distress, the children of God sing in adoration to His glory. It's easy to get caught up in the emotion of praise, so the Selah moments remind the believer to be still and consider the great importance of the words we sing. Who is worthy of all praise? God alone. For whom will the rocks cry out? God alone. Who is this King of Glory? The LORD Almighty! Selah