1st John 5:10

1st John 5:10 
The one who believes in the Son of God has the testimony in himself; the one who does not believe God has made Him a liar, because he has not believed in the testimony that God has given concerning His Son. 

The believer has the testimony in himself by virtue of what God has done for him. 

The unbeliever denies the testimony of God, that is, that God has done anything for him, and by rejecting the truth of what God has said and done, is effectively calling God a liar.

Question: For the alleged non-elect, who are excluded from the Atonement, and thus excluded from the “testimony,” how are they making God into a liar?

Answer: It’s actually the Calvinists who are making God out to be a liar, by denying that the testimony is for all, when yet the testimony is that God does love all, and did send His Son to die for all, so that anyone can be spared from judgment.

The Scriptures can claim that unbelievers make God out to be a liar because what has been told to them has come from the Holy Spirit, and who confirms what they have rejected. Otherwise, if the Son was not sent for them, then the Scriptures could not declare that they have rejected the testimony. So not only does this disprove Limited Atonement, but it also shows that people are not merely left to their own devices but that God actively intervenes, confirming the testimony to each person who has heard its message. As Jesus also has stated in John 15:22: If I had not come and spoken to them, they would not have sin, but now they have no excuse for their sin.