Jesus was begotten of the spirit at his baptism. However, the context of Psalm 2 is in keeping with the Apostle Paul’s application that the statement, “this day have I begotten thee” describes Jesus’ resurrection. Psalm 2 opens with the heathen raging and the kings of the earth setting themselves against God and His anointed (verses 1, 2). In other passages, Satan is described as “the god of this world” (2 Corinthians 4:4) and “the prince of the power of the air” (Ephesians 2:2). He rules this heathen world and governments. But it is part of God’s plan to destroy his empire and establish Christ’s kingdom. This is described in Psalms 2:4-6.
“He that sitteth in the heavens shall laugh: the Lord shall have them in derision. Then shall he speak unto them in his wrath, and vex them in his sore displeasure. Yet have I set my king upon my holy hill of Zion.” The king described here is Jesus. His reign will see the end of Satan’s kingdom.
This is the context that immediately precedes verse 7, which says, “I will declare the decree: the LORD hath said unto me, ‘Thou art my son; this day have I begotten thee.” Although Jesus was begotten of the spirit at Jordan, he was born of the spirit at his resurrection. He then received full authority to carry out all the other features of God’s plan. One aspect of that is described in Psalm 2, the removal of Satan’s empire. This authority is stated in verse 8, “Ask of me, and I shall give thee the heathen for thine inheritance, and the uttermost parts of the earth for thy possession.”
Then in Acts 13:12,13, Paul is reassuring fellow Christians that the promise made to Abraham would be fulfilled because Jesus was raised from the dead. “And we declare unto you glad tidings, how that the promise which was made unto the fathers, God hath fulfilled the same unto us their children, in that he hath raised up Jesus again; as it is also written in the second psalm, ‘Thou art my son, this day have I begotten thee.'”
There is a lot implied in Paul’s statement. Jesus’ resurrection proved that his sacrifice was acceptable and God’s promises would become reality. In Psalm 2 that meant Satan’s empire would be removed. In Acts, it means that God’s promise to bless all the families of the earth would also be fulfilled. They are the two great benefits that we will see because Jesus was raised from the dead and is now at the right hand of God.