to believe: to take a message as true and lean one's whole self on the person it is about, above all on God and on Jesus
This is the New Testament's central word for how a person responds to the good news. It is not split between head and heart. At one end it means accepting that something is so (that God raised Jesus, that God is one), and at the other it means handing yourself over to a person you have decided is reliable. The same verb carries both, because for the first Christians you could not really trust a person you did not also hold to be who they claimed to be, and you could not say you held Jesus to be Lord while keeping your weight off him.
The shades below track the small words the writers put after the verb.
- When it is followed by a statement ("believe that..."), the accent falls on accepting something as true.
- When it is followed by "in" or "on" a person, the accent falls on resting yourself on that person, which is the dominant note when the object is God or Christ.
- And used by itself, with no object at all, it had become almost a label: "those who believed" simply meant the Christians.
The early church did not invent this range. The Greek translation of the Old Testament had already used this verb to render the Hebrew word for Abraham's steady reliance on God (אמן), and Greek and Roman life used the related noun (πίστις) for the trust and good faith that held households, treaties, and loyalties together. So when the New Testament writers reached for this verb, they reached for a word that already meant a relationship of trust, and they aimed it at Jesus.
Because the word reaches from bare assent to self-surrender, no single English word captures it. "Believe" leans cognitive, "trust" leans relational, and the text keeps both in play.