What is the ruling on a student helping a classmate with their studies, and does anxiety about the classmate's exceeding her affect the reward for the help, and what is the clarification regarding the issue of divine decree (Qada') and destiny (Qadar) concerning exam results?

A student should have good intentions regarding academic excellence. Striving to fulfill the needs of Muslims and benefiting them is a great act of worship. She should purify her intention in helping those who need assistance, for Allah will reward her for her intention and good deed. True competition should be in matters of the Hereafter, as Wahib ibn al-Ward said, "If you can ensure that no one surpasses you in reaching Allah, then do so." As for worldly matters, provisions are in Allah's hands. One should supplicate for the competitors, and the servant is not held accountable for intrusive thoughts and whispers. It is incumbent upon the servant to take the necessary means and be keen on what benefits them, and not to rely solely on destiny.