Free from sin

1 Corinthians 1:18

“For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God.” NIV

The second thing you die to on the cross is sin.
Rom 6:1-14

“What shall we say then? Shall we continue in sin, that grace may abound? God forbid. How shall we, that are dead to sin, live any longer therein? Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life. 

For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection: Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin. For he that is dead is freed from sin. Now if we be dead with Christ, we believe that we shall also live with him: Knowing that Christ being raised from the dead dieth no more; death hath no more dominion over him. 

For in that he died, he died unto sin once: but in that he liveth, he liveth unto God. Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord. Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof.”

Yes I know this is along passage, but it speaks for itself. A dead person cannot sin because he is freed from the hold of sin. Because of the cross, you can “let not sin reign in your mortal body”. To live this out in reality, you count yourself dead to sin. Make a confession out this. Say, I am  freed from sin because I am dead. Therefore sin has no more hold on me, sin does not have dominion over me and I will not yield my body to it anymore.”
 When you make the confession, call the particular sin you are struggling with, pornography, lying, sexual sin, etc, by name.

“Neither yield ye your members as instruments of unrighteousness unto sin: but yield yourselves unto God, as those that are alive from the dead, and your members as instruments of righteousness unto God. For sin shall not have dominion over you: for ye are not under the law, but under grace.” Romans 6:13,14. KJV