You HAVE to believe eternal security to be saved

If you believe you can lose your salvation, then you are trusting in your works to keep your salvation.

1 John 5

10 He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son.

11 And this is the record, that God hath given to us eternal life, and this life is in his Son.