John 3:16 says, …whoever believes in Him shall not perish, but have eternal life (i.e. the life of the age to come).
It sounds as if you only have to believe in Jesus to attain eternal life. This assertion suggests that not even an understanding of the death and resurrection is essential to salvation.
The problem comes with the Greek verb pisteuo, which gets translated almost every time as “believe.” The verb actually carried with it the combined commitment involving trust, loyalty, and obedience. These three ingredients are absolutely crucial to both understanding the meaning of pisteuo and recognizing the standards which Jesus expect of his followers. The same can be said of the noun pistis.
Consider the parallel from Josephus, who describes an incident where he encountered a rival political revolutionary and attempted to persuade him to give up his fight: “I was not a stranger to that treacherous design he had against me, nor was I ignorant by whom he was sent for; that, however, I would forgive him what he had done already, if he would repent of it, and be faithful to me hereafter (εἰ μέλλοι μετανοήσειν καὶ πιστὸς ἐμοὶ γενήσεσθαι)” (Life 1:110). The act of becoming faithful to Josephus clearly involved a turning away from one’s former manner of life, submitting to Josephus as the new leader, following him, and obeying his commands.
The understanding that “belief” encompasses trust, loyalty, and obedience can be observed in John 3:36, where one can either “believe in Jesus” or disobey him.
Obedience to Jesus means adhering to his commands. The first command of Jesus, according to Mark 1:14-15, is to repent and believe in the gospel of the kingdom. Therefore, one cannot believe in Jesus without believing in his gospel, which is defined as the message about the coming kingdom of God, a kingdom to be consummated upon the earth at his return.