26. God’s Name in Vain
6:4 A person should be careful not to recite a blessing in vain or even to recite one unnecessarily. If a person makes a mistake and does so – or, if he utters God’s Name in vain in another context – he should immediately say “Baruch sheim kavod malchuso l’olam vo’ed” - ''Blessed be the Name of He Whose glorious kingdom lasts forever.” If a person started to say a bracha and got as far as “Baruch atah Hashem” before realizing that the blessing was being recited in error, he should complete it “lamdeini chukecha,” “teach me Your statutes. ”This is a verse in Tehillim (Psalms 119:12) and reciting it keeps the Name of God from having been uttered in vain. If the person started to say “Elokeinu” and got as far as “Elokei,” he should complete by saying “Yisroel avinu mei’olam v’ad olam,” “(of) our father Israel, forever and ever.” This is a quote from Divrei HaYamim (I Chronicles 29:10). In any event, a person should follow with “Baruch sheim kavod…”
6:5 Previously, people had local communal sources of water, such as wells. Upon hearing that a neighbor had died, people would spill out the water they had already drawn, just in case there was something wrong with it. If a person had said the blessing for the water but heard a neighbor had died before he could drink, the halacha was that he should take a sip before spilling it out. This keeps the blessing from having been in vain and the person is protected in merit of the bracha he recited as per Koheles (Ecclesiastes) 8:5, “The one who observes a commandment will know no evil.” (This is similar to the concept of giving travelers “shaliach mitzvah” money to deliver – see Talmud Pesachim 8a.)