Praise ye the LORD. Praise God in his sanctuary: praise him in the firmament of his power. Praise God in his sanctuary - In many places we have the compound word יה-הללו halelu-yah, praise ye Jehovah; but this is the first place in which we find אל-הללו halelu-el, praise God, or the strong God. Praise him who is Jehovah, the infinite and self-existent Being; and praise him who is God, El or Elohim, the great God in covenant with mankind, to bless and save them unto eternal life.
In his sanctuary - in the temple; in whatever place is dedicated to his service. Or, in his holiness - through his own holy influence in your hearts.
The firmament of his power - Through the whole expanse, to the utmost limits of his power. As רקיע rakia is the firmament of vast expanse that surrounds the globe, and probably that in which all the celestial bodies of the solar system are included, it may have that meaning here. Praise him whose power and goodness extend through all worlds; and let the inhabitants of all those worlds share in the grand chorus, that it may be universal.