How did Christ become a blessing to the whole human race?
Christ came through Abraham's line as the Messiah, finished the work of the cross, and thereby became a blessing out of Abraham's seed for the whole human race. This fulfilled the covenant promise that through Abraham all nations of the earth would receive a blessing.
Les explains that the covenant promise to Abraham included a secure promise that through the man Abraham all the nations of the earth would receive a blessing. That blessing came about with Israel's Messiah. When Christ came and finished the work of the cross, He became a blessing out of the line of Abraham, but a blessing for the whole human race. Les also connects this to Romans chapter 11, where natural Israel was broken off, Gentiles were grafted in, and Israel was set aside.