Is it a condition to know the meanings of the morning and evening adhkar—such as the meaning of "malignant" (hammah) and "envious" (lammah) in the supplication "I seek refuge in Allah's perfect words from every devil and every malignant eye and every envious eye"—for the reciter to benefit from them?

It is better for the one who remembers (Allah) and supplicates to understand the meaning of what he supplicates with, for that is more effective in achieving presence of heart. However, that is not a condition for supplication or remembrance. For when the limbs become accustomed to good, until it becomes like second nature to them, it repels a multitude of sins. And supplicating with the traditional supplications whose meaning one does not know still achieves the desired purpose. The more complete way is for a person to know the meaning of what he supplicates with. So, "al-hammah" (الهامة) is any venomous creature that kills, and it can refer to any crawling animal. And "al-ayn al-lammah" (العين اللامة) is the eye afflicted with "lamam" (اللمم), which is a touch of madness that affects a person.