Counting 49 days up to the Omer.
Hebrew: ספירת העומר
The Omer is counted every evening after nightfall, from the second night of Passover till the night before Shavuot. There are 49 days of the Omer. The Omer signifies our preparation for the receiving of the Torah on the holiday of Shavuot. After Bnei Yisrael left Egypt they were in no condition to receive the Torah, and so 49 days, until Shavuot, were given so that they could cleanse themselves and prepare themselves to receive the Torah. For this reason, we count up to the Omer and do not countdown.
Blessing for Counting the Omer
בָּרוּךְ אַתָּה יְיָ אֱלֹהֵינוּ מֶלֶךְ הָעוֹלָם, אֲשֶׁר קִדְּשָׁנוּ בְּמִצְוֹתָיו וְצִוָּנוּ עַל סְפִירַת הָעֹמֶר.
Baruch Atah Adonai Eloheinu Melech HaOlam Asher Kideshanu B'Mitzvotav Vetzivanu Al Sfirat HaOmer
Blessed are You, Lord our God, King of the Universe, who has sanctified us with His commandments, and commanded us concerning the counting of the Omer.
The Laws of Sefirat Haomer
1) Sefirat haomer should be recited standing. Hazal found an allusion to this halachah from the pasuk, “From when your sickle begins on the grain, begin to count...” The word, “kamah” (grain) may be read, “komah,” implying an erect position. In any event, one who counted sitting has fulfilled his obligation and does not need to count again. Therefore, an elderly or sick individual who has difficulty standing may count sitting (even “lechatehilah”), as is the case regarding other misvot which are to be recited standing (hallel, milah, etc.).
2) The mitzvah is for each individual Jew to count himself, as the pasuk about sefirat haomer is written in plural form, suggesting that all members of the Jewish people must count the omer. Nevertheless, one can fulfill his obligation through the counting of another if both parties had in mind that the single counting should fulfill the obligation of the listener.
3) The counting is to be done at night. Ideally, it should be done after nightfall, approximately eighteen minutes after sundown. However, a congregation which concluded “Arbit” services immediately after sundown but before nightfall, a period about which we are unsure if it is night or day, and there is a legitimate concern that members of the community will forget to count later, they may count then with a bracha. However, under no circumstances may they count the omer before sundown, even on Erev Shabbat after services if the sun has not set.
4) One who forgets to count the omer at night but remembers the following day and counts then without a bracha may continue counting throughout the rest of the omer with a bracha. However, if the individual failed to count a complete day, he may no longer continue counting with a bracha for the Torah requires that the counting be complete. The same applies to one who counted incorrectly and did not correct his mistake throughout the entire day. He, too, may no longer count with a bracha.
5) One who is in doubt whether or not he counted on a given night, and knows that he did not count during the following day, he may continue counting the next night with a bracha since we have a double doubt. Since there are some views that this mitzvah is Biblical even today in the absence of the Bet Hamikdash, we may rely on the double doubt and continue counting with a bracha.
6) When who realizes during twilight (between sundown and nightfall) that he did not count the previous night or that entire day, should count immediately without a bracha and should then wait until after nightfall and count with a bracha.
7) One who counted the days but did not properly count the weeks may continue counting with a bracha.
8) One who is unsure of the day to count and has no way of clarifying what day it is in the omer should not count, as a doubtful counting is not considered a counting at all. If, however, he counted without a bracha and discovered on the following day that he was correct, he may continue counting with a bracha.
Based on the Aram Soba
Omer Count is an App available on the Google PlayStore and iPhone AppStore for counting the Omer. It keeps track of the days you have counted, sends an alert when it is time to count, coaches you and teaches you the Omer blessings in Hebrew and English