As to those that "believe in God", satan and the demons know God is real.Hebrews 10:23-25
<sup id="en-NASB-30157">23</sup>Let us hold fast the confession of our hope without wavering, for He who promised is faithful;
<sup id="en-NASB-30158">24</sup>and let us consider how to stimulate one another to love and good deeds,
<sup id="en-NASB-30159">25</sup>not forsaking our own assembling together, as is the habit of some, but encouraging one another; and all the more as you see the day drawing near.
Jesus said it takes a bit more.James 2:19
<sup id="en-NASB-30313">19</sup>You believe that God is one You do well; the demons also believe, and shudder.
You see, if you believe in Jesus as Savior and Lord then you will want to keep His commandments. Your life will reflect your belief with what you do. You won't be perfect, but you will seek perfection.John 14:15
<sup id="en-NASB-26684">15</sup>"If you love Me, you will keep My commandments.