Explanation of all the apparent redundancies of this posuk.
(25,8) “And you shall count for yourself seven sabbaths of years - seven years, seven times. And they shall be to you the days of seven sabbaths of years, forty-nine years.”
At first glance there seem to be much redundancy in this posuk. However, we can explain that if it had only written “you shall count for yourself seven sabbaths of years” I would have said that it is only necessary to enumerate the number of Shemittahs, but that there was no need to count the number of years themselves. That is, at the beginning of the first Shemittah cycle one should say "Today is the first Shemittah in the Yovel", and at the beginning of the second Shemittah cycle one should say "Today is the second Shemittah in the Yovel", but there is no need to count the number of years. Therefore it says “forty-nine years”, to teach us that we need to count all forty-nine years, each year separately.
But still I would have said that it is necessary to count the years separately only until the first Shemittah year is reached, but once the seventh year arrives one should say "Today is the first Shemittah". And when the eighth year arrives one should say "Today is eight years, which is one Shemittah", but there is no need to conclude "which is one Shemittah and one year" or "one Shemittah and two years", because there is no longer any need to count the years separately. Therefore it says “seven years, seven times”, to teach us that the years must be counted separately seven times, until one counts seven years seven times. That is, in every Shemittah cycle one should also count the years separately. From all this it is clear that it is necessary to first count the number of years of the Yovel by themselves, and afterwards to enumerate which Shemittah it is in the Yovel cycle, and also to enumerate which year it is in the current Shemittah cycle.
But still I would have said that it is necessary to count the Shemittahs only when each Shemittah year arrives, and also that it is not necessary to mention the Shemittahs that have already passed, only the current Shemittah. That is, when it is the third Shemittah one should say "Today is so many years, which is so many years of the third Shemittah", but there is no need to mention the Shemittahs that have already passed by stating "which is three Shemittahs and so many years". Therefore it writes “and they shall be to you the days of seven sabbaths of years, forty-nine years”, to teach us that all forty-nine years one needs to count all the days of the seven sabbaths of years, and mention in the counting all the previous Shemittahs. Thus, one must count the number of years in total, and also how many years it is in the Shemittah cycle, and also mention all the previous Shemittahs.
Therefore, this is also how we count the Omer. In the beginning we state how many days it is of the Omer and how many weeks have passed and how many days in the week. Because, as the gemora in Menachos says, it is a mitzvah to count days, and it is a mitzvah to count weeks. And we learn from the common expression “and you shall count” that is written both by counting the years of the Yovel and by the counting of the Omer, that just as by the Yovel cycle we need to count in general and in detail, mentioning also how many days it is in the Shemittah cycle and all the previous Shemittahs, so too must we count the Omer.
Now, the Tur brings several different opinions regarding the counting of the Omer. One opinion holds that we only need to count the days, and the weeks need to be counted only at the completion of the week. Another opinion holds that there is no need to count the total number of days separately, since one has already indicated how many days there are in the number of weeks and days. Another opinion holds that there is no need to count the weeks that have passed, but instead to say "Today is so many days, which is the nth day of the nth week". But the truth is that we are obligated by the Torah to count the way we are accustomed to do - "Today is so many days, which are n number of weeks and n number of days of the Omer" - as we see from the posukim.