A "watchman" watches outside his city to see if danger is coming. The prophet warning the people when they are sinning and are in danger of having his God punish them is spoken of as if he were a watchman for the city. AT: "The prophet is like a watchman for God over Ephraim" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This refers to prophets in general that God has appointed. AT: "Prophets are" or "True prophets are" (See: [[rc://en/ta/man/translate/figs-genericnoun]])
A "bird snare" is a trap used to catch a bird. This means the people of Israel do whatever they can to stop God's prophet. AT: "the people set a trap for him wherever he goes" or "the people do all they can to harm him" (See: [[rc://en/ta/man/translate/figs-metaphor]])
# They have deeply corrupted themselves as in the days of Gibeah
"The people of Israel have sinned and become very corrupt as they did at Gibeah long ago." This is probably a reference to the shocking actions of the tribe of Benjamin recounted in Judges 19-21.