In the days of the Holy Temple, the Mitzvah of counting the Omer was a Torah commandment, but nowadays – because of our faults – it is only a Rabbinic commandment.

Therefore, in the “Leshem Yichud” text recited before counting, one should not say: “I come to fulfill the ‘positive’ commandment of counting the Omer”, but “I come to fulfill the commandment of counting the Omer.”

The moment of the Sefira (counting): according to the strict law, one can start counting at sunset, but a priori, it is right to be rigorous and count after nightfall. If a person missed counting the Omer at night, he should count during the day, without saying a blessing.

Counting in the morning: it is a good custom to count the Omer every morning after the prayer, without blessing, so that the person who forgot to count at night could count during the day, and therefore may continue to count with a blessing.

Giving merit to many people: there is a nice custom in many communities: during the days of Sefirat HaOmer, between Mincha and Arvit (afternoon and night prayers), we read the Chapters of the Fathers (Pirkei Avot) and listen to a lesson given by a Master of the Torah until nightfall. Afterwards, we pray Arvit and count the Omer.

By this merit, the public may want to perpetuate this habit all year, since – as acknowledged – one Mitzvah brings on another Mitzvah.

One who causes the community to be meritorious, no sin will come by his hand.

The appropriate habit consists for the Chazan (leader of synagogue services) or Rabbi of the community in reciting the blessing and counting the Omer first, the audience repeating it afterwards.

It is best to do so in order to prevent people in the audience from making mistakes in counting.

If a community finishes praying at twilight and the Chazan knows that part of the audience will forget to count if he does not count right away, then it will be a Mitzvah for him to count without waiting for nightfall.

Error in counting: one who forgot to count both at night and on the following day may no longer continue counting with a blessing.

This person shall then ask someone else to associate him with the thought of the blessing but still count himself.

One who is unsure whether one has counted or not the day before, will continue counting the next day, reciting the usual blessing. A person who counted without saying a blessing is considered as having accomplished the Mitzvah but no longer has the opportunity to say the blessing that same evening.

Therefore, if one asks, “What day of the Omer is it today?”, the answer should not be: “Today is so many days of the Omer” (because that would in itself mean counting), instead the answer shall be: “Yesterday was so many days of the Omer.”

And by this answer, one will understand what must be the count of the day.

If by mistake one answered: “Today is such a day,” one may not recite the blessing in the evening. Nevertheless, if one did not say the word “Today”, one may continue counting with a blessing.

These rules are valid until the sixth day of the counting. From the seventh day on, the number of weeks also has to be mentioned, therefore in our case, where we answered only the number of days, it will be allowed to count with a blessing.

Initiation to the Mitzvot: it is a Mitzvah to educate the little ones to count the Omer with a blessing and even if they forgot to count one day, they may continue counting with a blessing.

Women are exempted from the Mitzvah of counting the Omer. Nevertheless, they can count if they wish to, but without a blessing.