Whom shall I send?. [ Isaiah 6 ]

There is a saying in the army, never volunteer,there is also a saying,never say never.My mind turns to the book of Isaiah,chapter six,there we read of God asking a question,/Whom  shall I send?.And who will go for us/.God
wanted someone to volunteer,and of course Isaiah did,He replied,/Here am I,send me/.Why did God not just command Isaiah to go,like he did with Jonah,I suppose if God had asked ,whom shall I send?,who will go for us,there would have been a  stony silence from Jonah,and he would have been guided by those words never volunteer. But both prophets went ,one reluctantly,the  other willingly.Isaiah had the harder task,for he was sent to Gods people,one just has to read Israels history,to appreciate how difficult
was the task Isaiah faced. Whereas Jonah had a relatively easier task ,the gentile people of Nineveh for they  repented and turned to God.God is still asking the same question ,whom shall I send,and who will go for us?,how are we going to answer ?
                                              A  prayer.
Dear God send forth labourers,into a world that is perishing,in Jesus name Amen.