Section 41(a) of the Inheritance Law deals with the provision "heir instead of heir":
"The testator may command two in order for the second to be rewarded if the first one does not merit; The second will be rewarded if the first person dies before the testator, or is found ineligible to inherit or has withdrawn from what he is entitled to, not for the benefit of his spouse, child or brother of the testator."
Sections 42(a) and 42(b) of the Inheritance Law deal with the "heir after heir" provision and its implications:
“)a) The testator is entitled to command two in order for the second to be rewarded after the first one has been rewarded; The second will be entitled to the death of the first or upon the fulfillment of the condition or upon the arrival of the date set for this in the will, all whichever is earlier.
(b) The first may do with what he received as his own, and the second will only merit what the first remains; However, the former cannot detract from the rights of the second by means of a will."
In the Zamir case, the difference was clarified by the Honorable Justice Naor:
"An examination of the two arrangements shows that the difference between them is great. In an "heir after heir" arrangement, which is set forth in section 42 of the law, the testator orders that upon his death, heir A will inherit the same heir; and the testator also instructs that after the death of heir A, the estate will be inherited by heir B. Until the property reaches heir B, there is, in the words of President Barak in the Melamed case (at p. 712), an "interim period", in which heir A is the owner of the property. Successor A, during this period, is entitled to "do with what he received as his own" (section 42(b)). The second heir will inherit only "what is left" from the first heir (ibid.). However, heir A is subject to a limitation: he may, indeed, treat the property as an owner's custom, but he is not permitted to detract from the share of heir B by means of his own will (ibid.). If, in our case, the arrangement set forth in the will of the mother of the applicants was an arrangement of "heir after heir", then the deceased could, indeed, transfer the property he inherited from his first wife to another during his lifetime, but he could not harm the balance of this property by changing the will (see A. Blecher-Prigat, "'Until Death Separates Us?' on the Doctrine of Mutual Wills in Israeli Law" (A. Barak and D. Friedman, eds., 5766 (497).