Without question, malice blocks the spiritual understanding of Christians, which is the same understanding Satan blinds in unbelievers. As it is written:
…whose minds the god of this age has blinded, who do not believe, lest the light of the gospel of the glory of Christ, who is the image of God, should shine on them. 2 Corinthians 4.4
Think about these questions:
Why does Satan blind the understanding of unbelievers?
He has blinded their understanding, precisely, so that unbelievers are prevented from knowing the Truth that sets them free.
Can he blind the understanding of believers?
Not in the beginning because of the Holy Spirit. But when believers embrace any kind of malice, especially the feeling of distrust in other people of the same faith, then the tendency of disbelief or willingness to see everything with evil eyes, for fear of being deceived, ends up nullifying the ability to understand the Word of God. This may be natural in the kingdom of this world, but never in the Kingdom of God, where everyone believes in the same Word.
For this reason, many good people who do not commit gross sins end up being contaminated with the malicious virus (distrust) and fail to develop faith for the salvation of their soul.
Read and meditate on the following verses:
The wicked is banished in his wickedness, but the righteous has a refuge in his death. Proverbs 14.32
Your own wickedness will correct you, and your backslidings will rebuke you. Know therefore, and see that it is an evil and bitter thing that you have forsaken the Lord your God, and the fear of Me is not in you, says the Lord God of hosts. Jeremiah 2.19
O Jerusalem, wash your heart from wickedness, that you may be saved. How long shall your evil thoughts lodge within you? Jeremiah 4.14
Brethren, do not be children in understanding; however, in malice (distrust) be babes, but in understanding be mature. 1 Corinthians 14.20