The verses say: Vayikra 23:15-16:

And from the day on which you bring the sheaf of elevation offering—the day after the shabbath—you shall count off seven weeks. They must be complete:

you must count until the day after the seventh week—fifty days; then you shall bring an offering of new grain to Hashem.

Finally we have a verse in Devarim 16:9

You shall count off seven weeks; start to count the seven weeks when the sickle is first put to the standing grain.

If 7 weeks is a כלל and 50 days is a פרט, then we have a sequence of כלל-פרט-כלל, which according the rules of Rabbi Yishmael must give priority to the פרט i.e. to counting days:

כְּלָל וּפְרָט וּכְלָל אִי אַתָּה דָן אֶלָּא כְּעֵין הַפְּ֒רָט.

6. A rule followed by a detail, which is in turn followed by a rule, may infer only what is similar to the detail.

Now the last כְּלָל is from Devarim, which is considered Derabannan for some opinions (r. Yishmael against r. Akiva). Therefore, we still count weeks after counting days.

This explains why, if one counted days but not weeks, according to Mishna Berura 489:1 S"K 7 (some opinions) bediavad one fulfills the obligation, but it's better to repeat without a bracha. That's because counting of days is more important. However if one counted weeks but not days - according to all opinions one did not fulfill the obligation. As clearly, counting of the weeks is less important.

The verses say: Vayikra 23:15-16:

And from the day on which you bring the sheaf of elevation offering—the day after the shabbath—you shall count off seven weeks. They must be complete:

you must count until the day after the seventh week—fifty days; then you shall bring an offering of new grain to Hashem.

Finally we have a verse in Devarim 16:9

You shall count off seven weeks; start to count the seven weeks when the sickle is first put to the standing grain.

If 7 weeks is a כלל and 50 days is a פרט, then we have a sequence of כלל-פרט-כלל, which according to the rules of Rabbi Yishmael must give priority to the פרט i.e. to counting days:

כְּלָל וּפְרָט וּכְלָל אִי אַתָּה דָן אֶלָּא כְּעֵין הַפְּ֒רָט.

6. A rule followed by a detail, which is in turn followed by a rule, may infer only what is similar to the detail.

Now the last כְּלָל is from Devarim, which is considered Derabannan for some opinions (r. Yishmael against r. Akiva). Therefore, we still count weeks after counting days.

This explains why, if one counted days but not weeks, according to Mishna Berura 489:1 S"K 7 (some opinions) bediavad one fulfills the obligation, but it's better to repeat without a bracha. That's because counting of days is more important. However if one counted weeks but not days - according to all opinions one did not fulfill the obligation. As clearly, counting of the weeks is less important.

The verses say: Vayikra 23:15-16:

And from the day on which you bring the sheaf of elevation offering—the day after the sabbath—you shall count off seven weeks. They must be complete:

you must count until the day after the seventh week—fifty days; then you shall bring an offering of new grain to Hashem.

Finally we have a verse in Devarim 16:9

You shall count off seven weeks; start to count the seven weeks when the sickle is first put to the standing grain.

If 7 weeks is a כלל and 50 days is a פרט, then we have a sequence of כלל-פרט-כלל, which according the rules of Rabbi Yishmael must give priority to the פרט:

כְּלָל וּפְרָט וּכְלָל אִי אַתָּה דָן אֶלָּא כְּעֵין הַפְּ֒רָט.

6. A rule followed by a detail, which is in turn followed by a rule, may infer only what is similar to the detail.

I.e. if one counted days but not weeks, according to Mishna Berura 489:1 S"K 7 (some opinions) bediavad one fulfill obligation but it's better to repeat without a bracha, however if one counted weeks but not days - according to all opinions one did not fulfill the obligation.

The verses say: Vayikra 23:15-16:

And from the day on which you bring the sheaf of elevation offering—the day after the shabbath—you shall count off seven weeks. They must be complete:

you must count until the day after the seventh week—fifty days; then you shall bring an offering of new grain to Hashem.

Finally we have a verse in Devarim 16:9

You shall count off seven weeks; start to count the seven weeks when the sickle is first put to the standing grain.

If 7 weeks is a כלל and 50 days is a פרט, then we have a sequence of כלל-פרט-כלל, which according the rules of Rabbi Yishmael must give priority to the פרט i.e. to counting days:

כְּלָל וּפְרָט וּכְלָל אִי אַתָּה דָן אֶלָּא כְּעֵין הַפְּ֒רָט.

6. A rule followed by a detail, which is in turn followed by a rule, may infer only what is similar to the detail.

Now the last כְּלָל is from Devarim, which is considered Derabannan for some opinions (r. Yishmael against r. Akiva). Therefore, we still count weeks after counting days.

This explains why, if one counted days but not weeks, according to Mishna Berura 489:1 S"K 7 (some opinions) bediavad one fulfills the obligation, but it's better to repeat without a bracha. That's because counting of days is more important. However if one counted weeks but not days - according to all opinions one did not fulfill the obligation. As clearly, counting of the weeks is less important.