Reference for Yevamot 123:18
מיתיבי
— There it is different, since Scripture mentioned his<span class="x" onmousemove="('comment',' Cf. supra p. 414, n. 9. ');"><sup>44</sup></span> own name as well as his father's<span class="x" onmousemove="('comment',' Which may indeed be taken as proof that idolaters' children are legal descendants and may be described as 'sons'. ');"><sup>45</sup></span> name, while here<span class="x" onmousemove="('comment',' Ziba's descendants. ');"><sup>46</sup></span> [the son's names] were not specified. If you prefer I might say: They<span class="x" onmousemove="('comment',' Idolaters. ');"><sup>47</sup></span> were elsewhere ascribed to their father and their father's father; as it is written, And King Asa sent them to Ben-hadad, the son of Tabrimmon, the son of Hezion, the King of Aram, that dwelt at Damascus, saying.<span class="x" onmousemove="('comment',' I Kings XV, 18. Cf. supra n. 9. ');"><sup>48</sup></span> It was stated: If a man had children and they died, he has fulfilled, said R. Huna, the duty of propagation. R. Johanan said: He has not fulfilled it. 'R. Huna said: He fulfilled' because [he follows the tradition] of R. Assi. For R. Assi<span class="x" onmousemove="('comment',' Others, 'Jose'. V. 'A.Z. 5a, Nid. 13b. ');"><sup>49</sup></span> stated: The Son of David<span class="x" onmousemove="('comment',' The Messiah. ');"><sup>50</sup></span> will not come before all the souls in Guf<span class="x" onmousemove="('comment',' Lit., 'body', the region inhabited by the souls of the unborn. ');"><sup>51</sup></span> will have been disposed of, since it is said, For the spirit that unwrappeth itself is from Me etc.<span class="x" onmousemove="('comment',' Isa. LVII, 16. This being the reason for the duty of propagation, the duty is fulfilled as soon as a child is born, i.e., as soon as his soul has left the region of Guf irrespective of whether he survives or not. ');"><sup>52</sup></span> And 'R. Johanan said: He has not fulfilled the duty of propagation' because we require [the fulfilment of the text] He formed it to be inhabited,<span class="x" onmousemove="('comment',' Isa. XLV, 18. ');"><sup>53</sup></span> which is not the case here.<span class="x" onmousemove="('comment',' The children being dead. ');"><sup>54</sup></span> An objection was raised: