We talk about "call" in Christian circles like it was the most ordinary thing. Everyone who is a believer these days is told whether literally or figuratively that they should sense a call to ministry. So it isn't any big deal when God calls you... right? Actually it is a VERY big deal when God calls you. Take a look with me at Isaiah's situation:
When God called Isaiah the first thing that happened was that Isaiah "saw the Lord". We live in a time when people want to see almost anything before they'll want to see the Lord. There's a lot of hot air out there from people (I provide a good deal of this pollution myself) talking about God and offering seminars and sermons on how to know him. But what would happen if you or I actually came in contact with the God Isaiah saw? He is "high and lifted up, and the train of his robe filled the temple." Now THAT is one cathedral-length train, for those of you who have ever gone wedding dress shopping.
There were angels (seraphim) flying above God in Isaiah's vision. It doesn't say exactly how many. Most times I think about this scene I want it to be down-sized so my brain can take it in. Maybe there are 2 angels, right? I don't think so. In Matthew, when Christ's birth is announced to a group of lowly shepherds on a hillside it says a "multitude of the heavenly host" showed up. Seems to me that if that's what people see on a warm June night off in one corner of the Middle East, if you were taken into the very throne-room of God you'd see a whole lot more!
So here is Isaiah standing... well... prostrate before God and a host of six-winged creatures who never sinned but who, in the presence of a holy God keep their faces covered out of respect and awe, and the effect on Isaiah is total: "I am undone. I am a man of unclean lips from a people of unclean lips." The number one thing Isaiah is thinking is that this is going to be the last moment of his life. But that's not what happens. Instead, in the midst of Isaiah's agony before God, the Lord sends one of the angels to minister to him, to cauterize his lips (the offending organ in Isaiah's confession), and to take away his sin.
Do I really allow myself to come in contact with a holy God? Or am I merely trying to live according to the rules (well... trying to bend the rules to my own pleasure while trying to make it look like I'm holy to everyone else)? A call from God is a call to holiness. It is a call to BE in the presence of God. I don't make myself "better" in order to engage in ministry. In fact, I shouldn't be praying that God would "convict me of sin and make me better." I should be praying, "God, take me into your presence. Let me experience YOUR holiness," and the rest will follow naturally.
Are you called to ministry? Great. I hope you hear his voice. But "Today, if you hear his voice, do not harden your hearts as in the rebellion, on the day of testing in the wilderness, where your fathers put me to the test and saw my works for forty years." I can play fast and loose with God's law in my heart while preaching righteousness and become nothing more than a moralizing fool, or I can simply allow myself to enter into The Presence and engage with him and do what Isaiah did: simply share what he saw.