Ramban

AND THOU SHALT COME UNTO THE PRIEST THAT SHALL BE IN THOSE DAYS — to the priest that shall be there in those days, for first-fruits, like all offerings, are given to the men of the [priestly] Division [who are assigned to the Sanctuary for a week at a time], but he may not bring along a priest from his city in order to offer him his first-fruits. Now, Rashi wrote: “You have none else than the priest who lives in your days as he is.” But I have not understood this, for in the case of an elder [of the Sanhedrin] it is proper to say [and thou shalt come …] unto the judge that shall be in those days, meaning that even though he is not as great and wise as the early judges in the ages which were before us, still he [the elder] is obligated to hearken to him [the judge], for “Jephtah in his generation is as Samuel in his generation.” But when bringing first-fruits, to whom shall he bring them if not to the priest that shall be in his days? Now, I have also seen the following text in the Sifre: 298. “And thou shalt come unto the priest that shall be in those days. This is what Rabbi Yosei the Galilean says, And would it occur to you to come to the priest that is not in your days? Rather, [I must say that the verse requires one to come to] the priest who is considered by you to be established and fit in those days. Kinsmen who have ceased to be kinsmen are qualified. And so it is also said, Say not thou: ‘How was it that the former days were better than these?’ ” thus refers to “the judges of the former days.” Do not say that the judges of the former generations were better than those of the present, and therefore I would not listen to them. Instead you are to listen to them, for you are only concerned with them (Maharsha, Rosh Hashanah 25b). It appears that the Sages interpreted in this connection that if one brought first-fruits or a burnt-offering to a priest who was presumed to be qualified and afterwards it was discovered that he was the son of a divorced woman, [a defiled priest not entitled to perform the Divine Service, nor to receive the priestly gifts] the offerings are nevertheless valid, as is mentioned in the last chapter of Tractate Kiddushin. Also included in this principle is [the rule] that a kinsman who has ceased to be a kinsman is qualified, this applying to an elder who may not be judged by a relative, but it is not relevant to first-fruits.
HIGAD’TI’ (I PROFESS) THIS DAY. “Through this fruit which I have brought I profess and give thanks to the Eternal your G-d Who brought me into the Land which He swore unto our fathers to give us. Thus G-d fulfilled His words, and I give thanks and praise to His Name.” The meaning of the word higad’ti is like “I have told.” So also ‘vayageid Mosheh’ (and Moses told) the words of the people unto the Eternal, which is in the past, when he has not made yet his declaration. Therefore Ramban writes that the very act of bringing the first-fruits into the Sanctuary Court constitutes a form of professing the omnipotence of G-d and an expression of thanksgiving to Him. In this sense the form of the word higad’ti is properly in the past, since the act of bringing the first-fruits has formed the way of communicating these thoughts. Such a usage is seen in the verse vayegeid Mosheh, which means that Moses “communicated” the words of the people to the Eternal. which means communicating. Or the interpretation thereof may be as follows: “I declare to you, O priest, and to all who stand by, and this declaration is unto the Eternal thy G-d, that is to say, to His Name, that I am come into the Land which He swore unto our fathers, for it is He Who brought me [near] to Him to serve Him in the Land.”