How can the requirement of four witnesses for adultery be applied in this age, given our knowledge that Islam is eager for concealment? And does this condition remain logical and valid for application in real-life cases similar to the example of entering water?

This issue is established by a clear Quranic text, and whoever denies it is an apostate. The Prophet, peace and blessings be upon him, and his companions acted upon it. Allah's rulings are wise and applicable in every time and place. Allah has stringent conditions for bearing witness to adultery to protect honor and to conceal the faults of His servants. The existing problems are not due to adherence to this ruling, but rather due to rebellion against Allah's law and imitation of His enemies. The solution lies in returning to Allah's law and applying it in all areas.