Why is belief in Christ's testimony essential for salvation?

Belief in Christ's testimony is crucial for salvation as it is through faith that a person receives eternal life. According to 1 John 5:12, 'He that hath the Son hath life; and he that hath not the Son of God hath not life.' This illustrates that receiving Christ's testimony is not merely an intellectual agreement but a spiritual awakening that signifies one’s adoption into God's family. Faith itself is a gift from God, indicative of having been chosen before the foundation of the world, thus demonstrating the believer's secure position in Christ. This belief enables Christians to experience the fullness of God's promises and the joy of their salvation.