This was God's specific ministry and call for the prophet. The impact of chapters 2 and 3 in Ezekiel may be lost on us because of an idea that is common in the church today, but one that is erroneous and that throws a wet blanket on the outreach of the church. Many would say this passage applies only to evangelists or pastors. As a result, a large portion of the body of Christ excuse themselves from the ministry of evangelism or outreach. In the church age every believer is a priest of God and called of God into full-time service of one sort or another according to their gifts.
Revelation demands an adequate response.
Opening the mouth portrays a teachable, hungry, and studious spirit. But if we don't open our mouths, if we aren't hungry, and if we don't make ourselves available, He can't feed and strengthen us in the Word. God was telling Ezekiel to thoroughly digest and understand the message. To be a student of the Word. We must know the message if we are going to be able to communicate it accurately.