Why was the exact date of Laylat al-Qadr concealed?
The wisdom behind this is to encourage Muslims to strive in worship throughout all the nights of Ramadan, or at least in the last ten nights. By doing so, they will earn the reward of observing Laylat al-Qadr as well as the reward of worshiping on other blessed nights.
What is the ruling on fasting?
Fasting in Ramadan is an individual obligation (Fard ‘Ayn) upon every mature, sane Muslim who is capable of fasting.
Fasting can also be recommended (Mustahabb), such as voluntary fasting on Mondays and Thursdays, fasting on the Day of Arafah for those not performing Hajj, and fasting on Ashura.
Fasting can be prohibited (Haram), such as fasting on the two Eid days, the Day of Doubt (Yawm al-Shakk), and the Days of Tashreeq.
Some types of fasting are disliked (Makruh), such as singling out Friday or Saturday for fasting without a specific reason and fasting on the Day of Arafah for a pilgrim.
I work overtime after regular working hours and may become occupied with my phone or the work computer for personal matters — what is the ruling on this?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
It is obligatory upon an employee to abide by the instructions and regulations governing overtime hours, and equally obligatory to uphold honesty and avoid all forms of deception and dishonesty. Allah the Almighty says {what means}: "O you who have believed, be mindful of Allah and be with the truthful." [Al-Tawbah/ 119]
Whoever is assigned to work overtime must be present at his workplace — even if he has no specific tasks to carry out at that time. In such a case, he should strive as best he can to spend that time in a manner that benefits the institution he works for. If there is genuinely no work for him to do, there is no objection to occupying his time with something beneficial — such as reciting the Holy Qurʾān, reading, or listening to educational lessons — provided he has already completed all the responsibilities assigned to him.
If, however, he does have work to complete, he must spend that time fulfilling it. He may attend to phone calls or other personal matters to the extent that is customarily acceptable, as long as this does not result in delaying or postponing his work. If he delays his work on account of personal preoccupations, the wages he received for that wasted time are not lawfully his to keep, and he is obliged to return the equivalent amount to the institution by whatever means available to him. And Allah the Almighty knows best.
Is it permissible for one who sacrifices on behalf of another, with the latter's permission, to eat from the sacrifice?
It is permissible for someone who sacrificed on behalf of another with their permission to eat from it with their permission, and they stand in their place (act as their representative) in distributing it.
It is stated in Nihayat al-Muhtaj ila Sharh al-Minhaj (Vol.8/P.141): "And he—meaning the one sacrificing on his own behalf, provided he has not apostatized—has the right to eat from a voluntary sacrifice and his sacrificial gift; rather, it is recommended. As for an obligatory sacrifice, it is forbidden for him to eat from it, whether it was designated as such initially or as a liability in his dhimmah. And excluded by what has preceded is if he sacrifices on behalf of another, or if he apostatized, then it is not permissible for him to eat from it, just as it is absolutely impermissible to feed a disbeliever from it."(The text I found indicates the impermissibility of eating) ???
And it is stated in Hashiyat al-Jamal ‘ala Sharh al-Manhaj (Vol.5/P.262): "If a person offers a sacrifice on behalf of a living person with their permission, does he act as their representative in distributing it—on the grounds that permission to sacrifice is permission to distribute it—or does it depend on their explicit permission? This requires consideration, but the first view is not far-fetched." And Allah the Almighty knows best.