Satan attacked the first people with lies. What God commanded them was not true. God's word was not trustworthy. God is not trustworthy.
Of course, the first people acted on these lies, and the world's DNA was infected by what the Bible calls "sin." There is now in man a tendency to move away from God. The God-man relationship is broken. The man-man relationship is broken. Man's relationship with himself is broken. His tendency is to choose directions, actions and attitudes that damages himself.
The cure is to choose to go away from, counter to this tendecy. THe first step is to declare the truth, because the devil's first step was to lie.
Satan will lie to us, just as he lied to the first people. It is the lie in our thoughts that will move us to make wrong decisions. Remembering and declaring truth will cancel the wrong thoughts.
Satan's lies will not always be obvious. It can be difficult to recognize the lie amid all the claims of "pleasure", "peace" and "profit." It can be difficult to recognize the lie among all the attempts to obscure it -- "old fashioned", "narrow-minded" and "judgmental." (Especially when the family of God underlines and highlights the lies with their own practices.) These are only a few of his lies to persudae us to follow his other lies. And if he succeeds in getting us to believe one of his lies, we will hear it again and again.
We need to live by the truth. To live by the truth, we need to know the truth. So, it is important to be engaged with God in the scriptures. It is important to obey God in making disciples. It is important to persist. Even if we succeed obeying God only once in a million times, God will take any step of obedience, of faith, and treat it like "bread and fish." (A reference to the story about Jesus feeding at least 5000 people with one person's lunch.)