That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith. That the blessing of Abraham - That is, justification or the pardon of sin, with all other blessings consequent on it, such as peace with God, spiritual life, and eternal glory.
Might come on the Gentiles through Jesus Christ - So we find that he was made a curse for us, that the blessings promised to Abraham might be given to them who believe on him, as having been made a curse; i.e. an expiatory victim for them.
The promise of the Spirit - The spirit of adoption, sonship with God; and the Spirit of God to attest that sonship. And all this was through faith. Hence, from the beginning God had purposed that salvation should be through faith, and never expected that any soul of man should be justified by the works of the law; and only gave that law that the exceeding sinfulness of sin might appear, and that man might be prepared to welcome the Gospel, which proclaimed salvation to a lost world through the atoning passion and death of Christ.