Peter warns believers not to give into fleshly lusts because they war against the soul. (1 Peter 2:11). Paul writes that the flesh and spirit are at war with one another (Galatians 5:17). He warns in Romans “If you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live” (Romans 8:13).
It is so easy to live according to the flesh. You simply do whatever you want to do regardless of the circumstances, long or short repercussions to self or anyone else. It is difficult to put to death the sinful or out of control desires of our bodies or emotions. To do that there is almost always suffering (Hebrews 5:5-8)
The end result putting to death lusts of the flesh is worth it though (Hebrews 12:11).