- A person who forget to insert the paragraph “May it please You” on Shabbos and already said the words “Blessed are You, Hashem” of the blessing “Who rebuilds Jerusalem,” but had not yet said the word בּוֹנֵה, “Who rebuilds” should conclude with the phrase לַמְּדֵנִי חֻקֶּיךָ, “teach me Your statutes,” and then return to recite the omitted paragraph and continue from there.
- If the person already said the word בּוֹנֵה, “Who rebuilds,” he should complete the blessing, then recite the following blessing: “Blessed are You, Hashem, our God, King of the universe, Who gave Sabbaths for contentment to His people Israel with love, for a sign and a covenant. Blessed are You, Hashem, Who sanctifies the Shabbos.” (Shulchan Aruch OC 188 with Mishnah Berura)
3. If he began the fourth blessing (“Who is good and Who does good”) and it is at the first two meals of Shabbos, he must return to the beginning of Bircas Hamazon. But if it is at the third meal, he does not have to repeat Bircas Hamazon (Ben Ish Chai; see also Bi’ur Halacha). [Some authorities maintain that if the person only reached the words מֶלֶךְ הָעוֹלָם, “King of the Universe,” and remembered there, he should continue with special blessing mentioned above (Chayei Adam; see also Mishnah Berura ibid.).