Are We Calling God a Liar?

“He who believes in the Son of God has the witness in himself; he who does not believe God has made Him a liar, because he has not believed the testimony that God has given of His Son. And this is the testimony: that God has given us eternal life, and this life is in His Son. He who has the Son has life, and this life is in His Son.”  I John 5:10,11  NKJV