Reference for Bava Batra 265:9
אמר ליה רבא לרב נחמן והא אפסקה הוא סבר יש לה הפסק ורחמנא אמר אין לה הפסק
lies in a case] like [the following] which [was] sent [by] R. Aha son of R. 'Awya: According to the view of R. Johanan b. Beroka, [if a dying man said], 'My estate [shall be] yours, and after you [it shall be given] to X', if the first was [one] entitled to be his heir, the second has no [claim] whatsoever beside the first, for this is not a [specific] expression of 'gift' but [rather] of 'inheritance', and an inheritance cannot be terminated.<span class="x" onmousemove="('comment',' V. p. 540, n. 10 and 11, supra. Similarly, in the case under discussion, if the dying man said, in reply to the question whether his estate shall be given to a certain person, 'To whom else? But after him it shall be given to a certain other person,' the second is entitled to receive it only if the first was not a legal heir and received it as a gift. ');"><sup>27</sup></span> Raba said to R. Nahman: Surely, he<span class="x" onmousemove="('comment',' The testator. ');"><sup>28</sup></span> has [already] intercepted it!<span class="x" onmousemove="('comment',' By making the assignment of the estate to the first conditional upon its being transferred later to the second. ');"><sup>29</sup></span> — He thought [erroneously] that it could be intercepted but the All-Merciful said, 'It cannot be terminated'.<span class="x" onmousemove="('comment',' Since the divine word prohibits interception of the succession no one has the right to make arrangements which disagree with it. ');"><sup>30</sup></span>