The common dua we use for Suhoor:
بِصَوْمِ غَدٍ نَوَیْتُ مِنْ شَهْرِ رَمَضَانَ
Translation: “I intend to fast tomorrow for this month of Ramadan”
Why do we use the word tomorrow غدا when the fast we are keeping is intact today?
Bismillahi Ta’ala
Walaikum Assalam Warahmatullah
At the outset it should be understood that intention for fasting is not required to be verbal. An intention in the heart for fasting is sufficient. So the wordings in the question have been accurately mentioned to be a “du’a” at the time of suhoor.
Secondly, the term “ghad” is from ghadwun (غدو) which normally refers to “tomorrow”, but is also applied “to a remote time that is expected (without any specification in the future)” as well as “to a near time (without of any specification)”.
Thirdly, from the angle that some fuqaha’ are of the opinion that intent for fast should be from the night before, these wordings accommodate an individual who would fast the morning that comes after the night.
Hence when we see among the shafi’i fiqh, they do mention that ghad is used in understanding that it refers to the day after the night that is connected with the intention (See Tuhfatul Muhtaj).
Keeping in line with customary usage of غدوۃ referring to the morning time, and that غدا can refers to the coming near time, it is also suitable even if one were to make this du’a before the suhoor time finishes. This time is still within the night of that day, so it is before the morning day (الیوم) begins.
Finally it is merely usage of wordings, so if someone make the du’a by saying
“بِصَوْمِ الیوم نَوَیْتُ مِنْ شَهْر رَمَضَانَ”
and intending the day coming forth, it will be perfectly fine as well.
Wallahu A’lam
And Allah Ta’āla Knows Best
Mufti Faisal al-Mahmudi