What does 1 Samuel 3:21 mean?

This verse suggests that, after this initial prophecy for Eli, the Lord continued to reveal information to Samuel for him to speak to others. Although the tabernacle and the ark of the covenant were at Shiloh, revelations from God were not frequent there before the time of Samuel (1 Samuel 3:1). Now that has changed. Shiloh has become known throughout Israel as the place where God speaks to His people through His official prophet Samuel (1 Samuel 3:20).

The sense in the land may have been that after the corruption of the house of Eli during his time as Israel's priest, the Lord was once again beginning to be at work among His people. God had declared that Eli and his household would be held accountable for their abuses of power as priests of Israel, a prophecy heard throughout the land, apparently (1 Samuel 3:11). Now the Lord had also stopped being silent and had begun to reveal His will to His people once more.

Still, darker times were ahead for God's people. They would be forced to choose to trust Him once more to deliver them from their enemies.