|>> The Bible says whoever curses Israel God will curse. <<|
I presume you are referring to Gen 27.29, where Isaac pronounces a blessing on Jacob, who was later given the name Israel:
"Let people serve thee, and nations bow down to thee: be lord over thy brethren, and let thy mother's sons bow down to thee: cursed be every one that curseth thee, and blessed be he that blesseth thee." (Gen 27.29)
The Bible makes it clear (to those who are spiritually minded), that Jesus Christ is the embodiment of the True Israel. The Israel of old was merely a shadow or a figure, but the reality is fulfilled in Jesus Christ.
It is plainly obvious that this verse is to be applied to Jesus Christ.
"Let people serve thee,"
There are multiple references in the New Testament speaking of the Christian nations serving Christ. (cf. Rom 14.18; Rom 16.18; Col 3. 24)
"and nations bow down to thee"
"For we shall all stand before the judgment seat of Christ. For it is written, As I live, saith the Lord, every knee shall bow to me, and every tongue shall confess to God." (Rom 14.10-11)
Wherefore God also hath highly exalted him, and given him a name which is above every name: That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth; And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father. (Phil 2.9-11)
"be lord over thy brethren"
But he answered and said unto him that told him, Who is my mother? and who are my brethren? And he stretched forth his hand toward his disciples, and said, Behold my mother and my brethren! For whosoever shall do the will of my Father which is in heaven, the same is my brother, and sister, and mother. (Mat 12.48-50)
Naturally Christ is Lord over his disciples, whom are his brethren.
The Church has always understood the blessing given by the patriarch Jacob to his son Judah as finding its ultimate fulfillment in Christ.
What did Leah proclaim after she bore Judah?
"Now will I praise the Lord: therefore she called his name Judah". (Gen 29.35)
So you see, the name of Judah is connected with praise of God, and not of men. Do not confuse praising (i.e. blessing) Israel after the flesh with praising the true Israel of God, Jesus Christ, and his holy Bride.
"Judah, thou art he whom thy brethren shall praise: thy hand shall be in the neck of thine enemies; thy father's children shall bow down before thee." (Gen 49.8)
Do you see once again? The name Judah is associated with praise.
St. Paul clarifies the concept quite plainly in the New Testament, for those who have ears to hear:
"But he is a Jew (Judah), which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God."
Yet again, we see the name Judah (Jew) associated with praise, but NOT of men, as you are perversely advocating, but of God, which includes our Lord Jesus Christ, the God-man.
True Christians have nothing to do with this Protestant perverseness whereby money-grubbing hucksters implore their deluded followers that they must praise a people after the flesh, who are nothing but counterfeits of the synagogue of Satan, falsely calling themselves Israel and Jews.
"We are esteemed of him as counterfeits: he abstaineth from our ways as from filthiness: he pronounceth the end of the just to be blessed, and maketh his boast that God is his father." (Wisdom 2.16)
Obviously this Old Testament prophecy pertains to Christ, who "boasted" that God is His Father, and the Scripture testifies that Christ Jesus esteemed the apostate Jews to be counterfeits, a brood of vipers, who had the devil as their Father, and not Abraham. (cf. John 8.44)
So, the traditional orthodox interpretation by Christians has always been: whomever curses Christ the true Israel, God will curse, and whomever blesses Christ, will be blessed.
The holy Apostle Paul summed this up very briefly when he wrote:
"If any man love not the Lord Jesus Christ, let him be anathema" (1 Cor 16.22)
It has always been traditional for a bride to take on the surname of her bridegroom. Hence the Bride of Christ, Holy Church, is also called Israel, after her Bridegroom, Christ.
Yet legions of Protestant mammon worshipers teach their disciples to bless a counterfeit people who are cursed or cut-off from God, for everyone knows the unbelieving Jews do not love the Lord Jesus Christ.