How can I overcome the whispers of Satan that beautify sins for me—such as missing prayers or masturbating—under the pretext that "Allah is Oft-Forgiving, Most Merciful" and that there are necessities that permit these actions, by relying on the Qur'an, the Sunnah, the sayings of scholars, and logic?

Do not follow the footsteps of Satan, who enjoins immorality and wrongdoing, and do not take him as a protector, for he is a clear enemy. Deliberately sleeping through prayer is a major sin among the gravest of major sins, and masturbation is a trick that does not deceive Allah, for Allah is not deceived. The mercy of Allah is attained by those who strive to achieve it and pursue its means, and it is not attained by those who rely on disobedience. "Indeed, the mercy of Allah is near to the good-doers." Repent with sincere repentance and observe prayers at their appointed times. Repent to Allah from masturbation, and strive to employ the means of repentance, such as fasting, supplication, keeping company with the righteous, and avoiding whatever leads to sin. Remember that the appointed time is near, and Allah is Forgiving and Merciful, forgiving all sins for those who repent.