I don’t know what you mean by God’s voice.
The Church calls the Bible the word of God. It also calls sacred tradition the word of God. If it passes on moral statements from the Bible, it then would be providing the word of God. This would start with the ten commandments of course, but also many other things from the New Testament, most famously the Sermon on the Mount in Matthew, which includes many statements about right and wrong. It this way they might be said to be God’s voice then (though I don’t know what you mean by this).
However, if what members of the Church hierarchy say does not come from Scripture or Tradition, such statements could not be said to be the word of God. Bishops and bishop’s conferences make many statements about moral issues, but of course they would not be the word of God, even for example the Pope’s statement against Nazism when Hitler was in power.