Jesus said:, "If anyone wishes to come after Me, he must deny himself, and take up his cross daily and follow Me.” Luke 9:23. People often want to know which cross Jesus was referring to. The cross is our flesh.
Our flesh is corrupt and seeks to please itself. When we find salvation and believe in Jesus Christ we have to force our flesh to obey the Holy Spirit, which Christ makes to dwell in us. Jesus said: "It is the Spirit who gives life; the flesh profits nothing; the words that I have spoken to you are spirit and are life.” John 6:63.
When we invite Jesus into our hearts our spirit is renewed (born again), but our soul keeps it’s sinful nature. We have two forces at work in us, the flesh with it’s carnal desires and the Spirit of God living in our spirit. If we live according to the flesh we must die. We thus have to deny the flesh its desires and force ourselves to obey the Spirit of Christ in us.
Our flesh is eternally corrupt, it will never change until the day we die. We are not all the same. Some people are weaker in some areas. It is a mistake to think that the flesh will ever change. We need to control ourselves and force the flesh to obey Christ. Some people say it is impossible to stop sinning. It is not or else Jesus would not command us to stop sinning.
The only way to follow Christ is to daily pick up our cross, crucify the flesh and force it to do the will of God. Obedience to Jesus is not optional, it is a requirement to enter the kingdom of heaven. God does not tolerate willful disobedience. The soul that sins will die.
If we constantly focus on Jesus and listen to the Spirit of Christ in us, it is possible to overcome the flesh. With God, all things are possible. We are able to do all things through Christ who strengthens us.