God's messengers
The usual Hebrew word translated “prophet” is nabi, which refers to someone called or appointed to speak for God. Moses gives a helpful picture when Aaron speaks to Pharaoh on Moses’ behalf, acting as Moses’ spokesman (Exodus 4:16, KJV). In the same way, a prophet spoke not simply personal opinions but the message God gave.
God promised Israel that he would raise up prophets and put his words in their mouths (Deuteronomy 18:18, KJV). That was a serious calling. Jeremiah, for example, was told that God had set him apart for this work before his birth (Jeremiah 1:5, KJV).
I will raise them up a Prophet from among their brethren, like unto thee, and will put my words in his mouth; and he shall speak unto them all that I shall command him.
More than predicting the future
Prophets did sometimes announce future events. Isaiah spoke of coming judgement and later comfort, while Daniel received visions about kingdoms. Yet prediction was not their whole job. Often they addressed what was happening right then: idolatry, dishonest leadership, mistreatment of the poor, or empty religious activity.
When Israel repeatedly turned from God, he sent prophets to urge the people to turn back and keep his commandments (2 Kings 17:13, KJV). Nathan confronted David after his sin against Bathsheba and Uriah. Elijah challenged Ahab’s devotion to Baal. Their words could be difficult to hear, but they were meant to draw people back to God.
Yet the Lord testified against Israel, and against Judah, by all the prophets, and by all the seers, saying, Turn ye from your evil ways, and keep my commandments and my statutes, according to all the law which I commanded your fathers, and which I sent to you by my servants the prophets.
A word for kings and ordinary people
Prophets did not only speak in royal courts. Samuel served Israel during a changing political era, and people throughout the land recognised that he was a trustworthy prophet of the Lord (1 Samuel 3:20, KJV). Isaiah spoke in Jerusalem, Amos came from the countryside of Judah, and Ezekiel brought God’s message among exiles in Babylon.
Their messages held both warning and hope. They exposed sin honestly, but they also reminded God’s people of his mercy and his promises. Even in exile, God spoke through Ezekiel to assure his scattered people that he had not abandoned them (Ezekiel 11:16, KJV).
Not every claimed prophet was true
The Old Testament also warns that some people claimed God’s authority when God had not sent them. A prophet’s message could not lead Israel away from the Lord, even if a sign or prediction seemed impressive (Deuteronomy 13:1-3, KJV). Nor could someone speak presumptuously in God’s name without consequence (Deuteronomy 18:20, KJV).
So a prophet was not a spiritual fortune-teller. A true prophet pointed people towards the living God and called them to covenant faithfulness. Reading the prophets can feel challenging, but it also opens up God’s patience, holiness, grief over evil, and lasting desire to restore his people.
And all Israel from Dan even to Beer–sheba knew that Samuel was established to be a prophet of the Lord.