The quote in verse 13 is from Deuteronomy 21:23. In Deuteronomy, the quote includes the words “of God.” Paul excludes them because Christ wasn’t cursed by God but by the law. The law satisfied its demands for punishment upon Christ and so He was no longer under its jurisdiction. Believers, by faith, are in the same position in Him.
tree (v.13) = item made of wood — here, the cross
In the Old Testament, the worst offenders were stoned to death and then their bodies were hung on a tree.
The very manner of His death involved the extreme of humiliation, disgrace, and shame. “For it is written, Cursed is every one that hangeth on a tree.” This quotation from the Old Testament refers to the Hebrew custom, in accordance with which, after a criminal was put to death, his body was suspended from a tree or a post. Crucifixion was not a mode of capital punishment among the Israelites, but the disgrace of execution was intensified thus by hanging. The latter was regarded as a witnessing in the presence of God that a just and sufficient penalty had been paid, and it was furthermore a testimony of God’s abhorrence of sin. According to the requirements of the Jewish law, the body must be buried before nightfall, but while it remained exposed it was a public proclamation that sin had been punished. This reference to the ancient Jewish custom is made by Paul to indicate how truly Christ, in His death, endured the utmost ignominy and suffering for the sins of the world, even while He Himself was sinless. He innocently bore the curse which was deserved by sinful men. His suffering, however, was endured in order that the blessings which had been promised to Abraham might come to all, of every race and nation, who wold put their trust in Christ. — Erdman, pages 64-65.
blessing (v.14) — favorable attitude that results in kind acts.
blessing of Abraham (v.14) and not the blessing of Israel because Israel was also condemned by the law.
Since the Jews were shut out from blessing by the very law in which they gloried, Gentiles could not hope to obtain it by putting themselves under that law. But if to the Jews the blessing was secured by the death of Christ, and in response to faith, then on the same ground, and on the same condition, the blessing would extend to the Gentiles also. — Vine, page 186.
in Christ Jesus (v.14) — This was something new, established on the cross. The blessing of Abraham was now available to Jew and Gentile through faith in Christ.
promise (v.14) — a gift given by grace and not a pledge obtained by negotiation or obligation.
The promise to Abraham was general — a blessing, without mention of the Spirit. Later Scriptures (Isaiah 32:15; Ezra 36:27) reveal that the Spirit was included in the blessing. But the complete fulfillment of these later promises — and the time when the Spirit will fully control believers — is yet to come.
The curse/punishment due to the law must be suffered by everyone either personally or through a substitute.
Prior to the Dispensation of Grace, a Gentile could only be saved by becoming a Jew.
Verse 14 is dependent on verse 13. Christ became a curse so that the blessings of Abraham would come on Gentiles and both Jews and Gentiles could receive the Spirit.