God is truth.
John 14:6 -- "Jesus told him, “I am the way, the truth, and the life. No one can come to the Father except through me."
God can only speak truth, without any omission or distortion. Lies only come from Satan.
John 10:10 -- "The thief’s purpose is to steal and kill and destroy. My purpose is to give them a rich and satisfying life."
When we lie we are choosing evil and not God. Even subtle decisions like white lies leave room for the devil to manifest and create distance between you and God. Satan's purpose is to steal, kill and destroy, so choosing a lie over the truth allows that destruction to make a foothold in your life.
We can never be perfect because we live in a fallen world, but we can repent and ask God to help us cease lying and speaking evil. God can help us overcome the lies of the world and live in His truth.
Help me to stay apart from evil and not tell lies. Help me to rely on You and live only in Your truth.