Nedarim

We learnt: A VOW WITHIN A VOW IS VALID, BUT NOT AN OATH WITHIN AN OATH. How is this? shall we say that one declared, 'Behold, I will be a nazir to-day. Behold, I will be a nazir tomorrow':  then an analogous oath is: 'I swear not to eat figs. I swear not to eat grapes,' why should this second oath be invalid? But the invalidity of all oath within an oath arises thus: 'I swear not to eat figs, I swear not to eat figs.' Then an analogous vow in respect of neziruth is: 'Behold, I will be a nazir to-day; Behold, I will be a nazir to-day; and it is stated, A VOW WITHIN A VOW IS VALID. This refutes R. Huna? — R. Huna answers you: The Mishnah applies to one who said: 'Behold, I will be a nazir to-day. Behold, I will be a nazir to-morrow;'  and an analogous oath is: 'I swear not to eat figs I swear not to eat figs and grapes,'  the second oath being invalid. But did not Rabbah Say: [If one says,] 'I swear not to eat figs,' and then adds, 'I swear not to eat figs and grapes'; if he eats figs, sets aside [an animal for] a sacrifice and then eats grapes, the grapes constitute [only] half the extent [of his second oath],  and a sacrifice is not brought for [the violation of] such. Front this we see that if one declares, 'I swear not to eat figs,' and then adds,' I swear not to eat figs and grapes': since the [second] oath is valid in respect of grapes, it is valid in respect of figs too? — R. Huna does not agree with Rabbah. An objection is raised; If one made two vows of neziruth, observed  the first, set aside a sacrifice,  and then had himself absolved thereof [sc. the first vow], the second is accounted to him in [the observance of] the first.  How is this? Shall we say that he declared, 'Behold, I will be a nazir to-day; Behold, I will be a nazir tomorrow', why does the second replace the first; surely there is an additional day? But it is obvious that he said: 'Behold, I will be a nazir to-day; Behold, I will be a nazir to-day.'