Each ARABIC NUMERAL to the right indicates a place where a phrase break is recommended. The numeral represents the number of the verse in which the break is to occur. It is added to the score to help the organist see the break as he plays. These numerals mark the end of each phrase of text, clarifying the textual phrase structure.
The SLURS indicate places where the poetic structure might suggest a break, but where a break would interrupt and obscure the meaning. A break should not occur at these places, as far as the text alone is concerned.
Note that most of the phrase breaks (marked by Arabic numerals) occur at the ends of lines or phrases. At these points the poetic structure and the phrase structure are in agreement.