When we view the visible church as a “field of wheat”,in Matthew 13, it is understood that the tares represent the unbelievers amongst the believing Congregation of the Lord. My question is, should the preached Word be directed foremost to the flock that gathers to be fed or to the unbelievers present that they would be warned of the wrath to come?
You state that ‘we view the visible church as a field of wheat in Matthew 13’ and while this is true because both believers (wheat) and unbelievers (tares) are in the church, it is also true of the world in general which Jesus highlights in verse 38. Nevertheless, there are many other passages of scripture which highlight the fact that there are both believers and unbelievers in the congregation (Matthew 7:21-23; 8:11-12; 13:1-9).
You ask whether the preached Word should be directed foremost to the flock that gathers to be fed or to the unbelievers present that they would be warned of the wrath to come. While you make it an either/or question it is actually should be a both/and question. While the preaching is addressed to ‘the congregation belonging to Jesus Christ’ we acknowledge that within the congregation there are also hypocrites (Lord’s Day 31).
Some have an optimistic view of the congregation and so only address believers; others have a pessimistic view of the congregation and only address unbelievers; but a biblical (realistic) view of the congregation is that there are both in the congregation. Therefore, we are called to both feed the flock of God as well as call those who are unbelievers to repentance and faith. Now it isn’t necessarily helpful to address them with the labels (believers or unbelievers) but descriptive in the way of experiential discriminating preaching, but that perhaps is for another question.