2:4 David envisioned God as ruler over all sitting on His royal throne in heaven not at all threatened or worried about the plan of the nations, but laughing at its futility. The figure of God sitting on His throne is a common one that the psalmists used (cf. 9:11; 22:3; 29:10; 55:19; 102:12; 113:5; Isa. 6:1).
2:5 God also spoke to the nations. What He said He spoke in anger because they had refused to submit to the authority of His king who was an extension of Himself.
2:6 Because God had installed His king on the throne of Israel any rebellion against him would be futile ultimately. God established the kings of Israel with greater or lesser stability on their earthly thrones depending on their submission to the throne in heaven. David was very faithful to represent God, though not completely faithful, so God established his throne quite solidly, which involved ability to control the nations around him. Jesus Christ was completely faithful to carry out God's will on earth. He will, therefore, completely dominate His enemies.
"Zion"is the name of the Canaanite city built on Mount Moriah that David conquered (2 Sam. 5:7). It became known as Jerusalem. Later "Zion"was the term used to refer to the top area of that mount where the temple stood.
