God, in His grace, gives Isaiah a vision of the heavenly throne room. Isaiah realizes how sinful he is when compared to a holy God. God shows Isaiah that he is forgiven as an angel touches his lips with a coal from the altar. Isaiah 6: 8 Then I (Isaiah) heard the Lord asking, “Whom should I send as a messenger to this people? Who will go for us?” I said, “Here I am. Send me.” 
Here we have Isaiah immediately responding to go on an unknown assignment for God. No other prophet responded as quickly as Isaiah did. Many, such as Moses, Gideon, Jeremiah had excuses why they couldn’t go. Jonah actually ran away from his assignment. The experience of seeing the awesomeness of God and being forgiven opened the heart of Isaiah and made him a willing prophet. Granted, as we will see, Isaiah will ask God to clarify the length of this difficult call, but He is still a willing messenger.
The Lord also calls us to be messengers. Romans 10: 13 For “Everyone who calls on the name of the Lord will be saved.” 14 But how can they call on him to save them unless they believe in him? And how can they believe in him if they have never heard about him? And how can they hear about him unless someone tells them? 15 And how will anyone go and tell them without being sent? That is why the Scriptures say, “How beautiful are the feet of messengers who bring good news!”
16 But not everyone welcomes the Good News, for Isaiah the prophet said, “Lord, who has believed our message?” 17 So faith comes from hearing, that is, hearing the Good News about Christ.
This call isn’t easy but as followers of Jesus, it is His command. Matthew 28: 20 Teach these new disciples to obey all the commands I have given you. And be sure of this: I am with you always, even to the end of the age.” 
This can be a difficult task because many won’t listen. Jesus wants everyone to know what He has done for them. He suffered a horrible death so that all of humankind could be reconciled to the Father. The only way for that truth to be known is for someone to tell it. We are that “someone.” Why should we tell others? We should tell others because they need to know that Jesus loves them and longs to give them life. He desires to rescue each one from the pit and consequences of sin.
When you are afraid of telling others about Jesus remember this verse from Luke 12:12. For the Holy Spirit will teach you at that time what needs to be said.”  You may be the person God uses to change someone’s eternal destiny!
To hear more about the call of Isaiah, listen here: https://podpoint.com/light-of-christ-church-podcast/the-call-isaiah