"Every spiritual blessing in the heavenly places" can be attained all at once in Christ only by believing in the Gospel Truth. Heavenly blessings can never be found outside of Christ who came by the Gospel. These spiritual blessings that we have received did not come from the works of man, but they were fulfilled by the works of God.
The Apostle Paul states that these blessings originated from God the Father who chose us before the foundation of the world and from the ministry of Jesus Christ. Our true faith is not to relay on our own works, but we may define that it is to believe in God's good benevolence.
Now Paul says that God the Father "chose us in Christ before the foundation of the world." This means that salvation is a blessing that is bestowed to those who accept His benevolence. Those who were chosen in God's love. Paul explains the mystery of God and makes it clear that it is because God first loved us that our salvation has been made possible.