Is shunning the two friends mentioned in the question—one who does not believe in God and the other who believes in God but permits himself adultery and says that Satan is merely an expression of evil—tantamount to nullifying good deeds? And does the aforementioned Hadith Qudsi about a servant's discontent and its consequences apply to the questioner's situation, where he strives to improve his body but sees no results? Is this pursuit considered a displeasure with God's decree or not?

You must dedicate yourself to learning the Islamic sciences, consistently pray in the mosque, protect yourself from the Fire, and be keen on guiding those you meet among people, based on what is established in Islamic law concerning the emphasis on enjoining truth and patience, and mutual admonition among Muslims. You should also avoid associating with these two friends unless you are certain that you will not be negatively affected by them, but rather will influence them positively. Improve your religious state, take care of your health, strengthen your body, seek Allah's help, and remember Him when eating, drinking, and entering (a place), and do not let what you feel in your body hinder you from attending prayers in the mosque.