During fasting, is it permissible to put water in the mouth when performing ablution?

The Prophet, peace and blessings be upon him, commanded the complete performance of ablution (wudu') and exaggeration in sniffing water into the nose (istinshaq) and rinsing the mouth (madhmadah), except for the fasting person, so that water does not enter his stomach. Therefore, merely rinsing the mouth for a fasting person is permissible and does not invalidate the fast. This is indicated by the Prophet's, peace and blessings be upon him, statement to Umar ibn al-Khattab when he kissed while fasting: "What do you think if you rinse your mouth with water while you are fasting?" This shows that rinsing the mouth does not invalidate the fast.