What is the difference between a נֶדֶר (neder) offering and a נְדָבָה (nedava) offering? On first glance this may simply seem like a question of semantics, but its answer is needed to understand the analysis in today’s daf (Nazir 25a) of Vayikra 22:18 from which we learn that מוֹתַר נֶדֶר יְהֵא לִנְדָבָה – the surplus of a ‘neder’ shall be for a ‘nedava’.
Technically, the answer to this question is that a נֶדֶר (neder) is where a person commits themselves to bring an offering but only, at a later stage, consecrates a specific animal for that purpose, whereas a נְדָבָה (nedava) is where a person consecrates a specific animal for the sake of being brought as an offering.
However, the Ramban (commentary to Vayikra 22:18), though agreeing to these definitions, believes that the distinction runs much deeper in terms of what each expresses about the state of mind of the person making the נֶדֶר (neder) or נְדָבָה (nedava).
Specifically, he notes that whenever a נֶדֶר (neder) is referenced in the Torah we find that the word פלא – meaning ‘incredible’ or ‘wondrous’ – is also used (eg. Vayikra 22:2, Vayikra 27:2, Bemidbar 6:2, Bemidbar 15:3, Bemidbar 15:8). What this means is that a נֶדֶר is a vow that someone makes to God when they are in distress (see, for example Bereishit 28:20, Bemidbar 21:2, Yonah 1:16) to expresses their hope that God will do something incredible or wonderous to help them with their situation. And when this happens, a person commits themselves to bring an offering, but at that moment, they don’t have a specific consecrated animal in mind. Simply put, there is a lag between their words and their actions.
In contrast, a נְדָבָה (nedava) is a commitment that someone makes not from a state of distress that their situation will miraculously improve, but rather, from a state of feeling spiritually motivated and inspired at which point they seize the opportunity to consecrate a specific animal for the sake of being brought as an offering. At that point their words and actions operate in the same moment.
On the basis of this distinction perhaps it is possible to suggest that when our Gemara informs us that מוֹתַר נֶדֶר יְהֵא לִנְדָבָה – ‘the surplus of a ‘neder’ shall be for a ‘nedava’’ it can be understood to mean that when a person goes through moments of distress, and cries out to God to help them with their situation, then notwithstanding the challenges that this person has gone through they often come out of such situations feeling motivated and inspired, and with the belief that we shouldn’t wait to put our words into actions – because life is fragile, and we must seize every opportunity we have to make a difference in the world.