What is the supplication one can make to ward off the schemes of people, and does the wronged person's not retaliating against the one who wronged him lead to the forgiveness of his sins?

The best supplications in this regard are seeking refuge with Allah by reciting Surah Al-Ikhlas and Al-Mu'awwidhatayn (Surah Al-Falaq and Surah An-Nas), and frequently asking Allah for well-being (Al-Afiyah). In the Hadith: "Say 'Qul Huwa Allahu Ahad' (Surah Al-Ikhlas) and Al-Mu'awwidhatayn when you enter the evening and when you enter the morning, three times, they will suffice you against everything." And concerning Al-Mu'awwidhatayn: "People have not sought refuge with anything better than them." The Prophet, peace and blessings be upon him, would not abandon these supplications when he entered the evening and when he entered the morning: "O Allah, I ask You for well-being in this world and the Hereafter. O Allah, I ask You for forgiveness and well-being in my religion, my worldly affairs, my family, and my wealth. O Allah, conceal my flaws and calm my fears. O Allah, protect me from what is in front of me and behind me, from my right and my left, and from above me, and I seek refuge in Your Greatness from being unexpectedly struck from beneath me." And in the Hadith: "Ask Allah for forgiveness and well-being in this world and the Hereafter, for if you are granted forgiveness and well-being in this world and the Hereafter, you have indeed succeeded."