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 of Islamic Law on participating in the prize draws (raffles) that commercial stores hold for their customers?
Praise be to Allah, and peace and blessings upon our master, the Messenger of Allah.
There is no objection to participating in the prize draws (raffles) that commercial stores hold for their customers, provided that the buyer's intention in purchasing is not merely to enter the competition without any need for what is bought — rather, the purchase must be genuinely intended for the item itself, and one must not pay more than the item's fair market price. This is because paying an amount above the market price would effectively be paying a fee to enter the prize draw, which would render it a form of gambling (qimār).
These prizes are, in essence, gifts that businesses offer through a random drawing (qur'ah) to those who purchase from them, as a means of encouraging sales, without the customer bearing any additional monetary cost for participation. So long as the aforementioned conditions are met, there is no objection to benefiting from the prize offered by the store, as it is considered a lawful prize from the viewpoint of Islamic Law.
It is stated in the resolutions of the "Jordanian Iftaa' Board" (Resolution No. 47), in the context of outlining the conditions for permissible prizes: "The price of the ticket [or item purchased] for the sake of the prize must not exceed its original price, so that there is no payment of money in exchange for participation in the draw." And Allah, the Most High, knows best.
What is the ruling on istinja' after urination, and is it done with water and soap or with water only?
Istinja' from urine and stool is obligatory. It is permissible to perform istinja' with water alone, or with toilet paper alone. The best way is with toilet paper then water. If one wishes to suffice with one of them, then water is better. And Allah the Almighty knows best.
Should missed Sunnah prayer be made up?
Making up missed voluntary acts of worship is from Sunnah.