The Laws of Prayer /Shema (52)

1. Chazal decreed that in the morning services one must say the expression “Who forms light and creates darkness”, to mention the creation of darkness during the day, to disprove the erroneous opinion of those people who claim that He who created light did not create darkness. (Shulchan Aruch 59)

2. One must pause between the word “Yotzer” and the word “or”, so that the words will not join together and sound like one long word “Yotzeror”. (Mishne Berurah ibid)