What is the intention for combining and shortening prayers (al-Jam‘ wal-Qasr), and what should a traveler say if he prays Dhuhr two rak‘ahs during its time, intending to shorten it, and then follows it with ‘Asr?

It is permissible for a traveler to combine and shorten the four-rak'ah prayers if they have covered the distance for shortening. It is not a condition to vocalize the intention for shortening or combining; rather, it suffices to have it present in the heart. Combining is done by performing the Asr prayer before the Dhuhr prayer.