We read in Genesis 12:3 "And I will bless them that bless thee, and
  curse him that curseth thee: and in thee shall all families of the earth be
  blessed."
  Today many American Baptists, Pentecostals, and like-minded Christians
  believe the above passage is justification for financing the migration of Jews
  to Israel. Luther comments on the interpretation of this verse in Volume 2,
  page 262-264 of Luther's Works as follows:
  "But consider this too: whether those who bless the Jews and
  intimately associate with them are blessed. There are obvious examples, not
  only of private individuals but also of great princes, who can bear witness
  concerning this blessing that they experience because of their intimacy with
  Jews, namely, that they are being ruined with respect to fortune, body, and
  soul.
  "But perhaps the Jews will object that the psalm (109:11) says: 'May
  the creditor seize all that he has; may strangers plunder the fruits of his
  toil!' They will say that the Jews do not experience this from Christians, but
  the Christians from the Jews; for it is well known how much harm they cause
  the state with their excessive interest."
  'My answer is this: In the first place, reason itself teaches that interest
  or usury is contrary to nature and for this reason is actually a sin.
  Therefore Christians have the rule (Luke 6:35): 'Lend, expecting nothing in
  return.' Those who are disciples of Christ observe this rule and beware of
  interest as of a real sin. Moreover, experience also shows that riches gained
  in this manner are cursed by the Lord and do not last. Therefore if the Jews
  consider interest or usury a blessing, let them enjoy it. For it is certain
  that it is a sin; and a sure penalty is attached to this sin, as Scripture
  teaches again and again, and as the Jews themselves prove by their own
  example." . . .
  "Hence this is a most powerful argument to support our religion and
  faith and to refute the deceitful Jews, namely, that they have lost everything
  promised here to Abraham, and especially what is promised last, that the
  blessing will spread from the seed of Abraham to all the families of the
  earth."
  "They are hard pressed by this reasoning. Therefore they prate that
  this statement was fulfilled in Solomon, the son of David, and that he was
  blessed by the nations, that is, was renowned and was praised by everybody.
  But what has it to do with the text if he was blessed or praised by others?
  What the words mean is this, that this seed will bring a blessing to all
  nations. Now what did Solomon bring to the nations?"
  "Therefore this text clearly compels us to confess that the Messiah or
  Christ has long since come and was revealed, and that He brought a spiritual
  and eternal blessing with Him into the world. When the unbelieving Jews
  rejected this and would not have it, it was brought to the heathen. But the
  wretched Jews were deprived of both their material and their spiritual
  blessing, as experience demonstrates. They have now been living for almost one
  thousand five hundred years under great hardships and in uninterrupted
  captivity, and they have nothing of the promises of which the Lord is speaking
  here. If God is truthful in His promises, then they must be liars; and through
  their unbelief they have forfeited these promises and are no longer the seed
  of Abraham to which these promises were given."
  Apart from Luther's comments above, the greatest blessing that can be given
  to anyone is the saving Gospel of Jesus Christ. This Gospel only comes from
  the mouths of Christians.
  Romans 10:1 Brethren, my heart's desire and prayer to God for Israel is,
  that they might be saved. 2 For I bear them record that they have a zeal of
  God, but not according to knowledge. 3 For they being ignorant of God's
  righteousness, and going about to establish their own righteousness, have not
  submitted themselves unto the righteousness of God. 4 For Christ is the end of
  the law for righteousness to every one that believeth. 5 For Moses describeth
  the righteousness which is of the law, That the man which doeth those things
  shall live by them. . . .19 But I say, Did not Israel know? First Moses saith,
  I will provoke you to jealousy by them that are no people, and by a foolish
  nation I will anger you. 20 But Esaias is very bold, and saith, I was found of
  them that sought me not; I was made manifest unto them that asked not after
  me. 21 But to Israel he saith, All day long I have stretched forth my hands
  unto a disobedient and gainsaying people.