Is proficiency in worldly sciences and strong competition in them essential for establishing the religion, and that for the Hereafter to be in the heart, the worldly life must be in the hand, as is evident from the biography of Khalid ibn al-Walid and the verse {فأتبع سببا} (he followed a way)?

Studying worldly sciences that the Ummah needs is a collective obligation (fard kifayah) and is considered part of the preparation commanded by Allah in His saying: (And prepare against them whatever you are able of power). The greatest preparation is preparing the monotheistic Muslim individual who employs these sciences to support his religion and benefit his Ummah.