Dhikr with an example.

The Shaykh : The second condition is dhikr, and its opposite is... wait, did you pay attention?
The student: ... .

The Shaykh : Where did you go? With me, okay, rest. It says that the opposite of dhikr is silence, but the correct view is that the opposite of dhikr is forgetfulness. The Prophet (peace and blessings be upon him) said: So the opposite of dhikr is forgetfulness. If a person eats while fasting, forgetting that he is fasting, we would tell him: your fast is valid, you owe nothing, and continue with it.