Reference for Nedarim 6:5
אמר מר ומה נדרים עובר (במדבר ל ג) בבל יחל ובל תאחר בשלמא בל יחל דנדרים משכחת לה כגון דאמר ככר זו אוכל ולא אכלה עובר משום בל יחל דברו
The Master said: 'And just as in other vows, he who does not fulfil them violates the injunctions, he shall not break his wad, and thou shalt not delay to pay it, so in neziroth.' Now, as for 'he shall not break his word' as applying to [ordinary] vows, it is well: it is possible e.g., if one says, 'I vow to eat this loaf', and does not eat it; he violates the injunction, 'he shall not break his word'. But how is, 'he shall not break [his word],' possible in the case of neziroth.? For, as soon as one says, 'Behold, I am a nazir' he is one; if he eats [grapes], he is liable for, nor eat moist drapes or dried;<span class="x" onmousemove="('comment',' Ibid. VI, 3. ');"><sup>5</sup></span>