MAKE SURE NOT TO DO IT ALONE...

1 Unless the Lord builds the house, those who build it labor in vain.Unless the Lord watches over the city, the watchman stays awake in vain. 

2 It is in vain that you rise up early and go late to rest, eating the bread of anxious toil; for he gives to his beloved sleep. (Psalm 127: 1-2, ESV)

If I maybe allowed to put it in other words:

Unless the Lord is behind/in our sermons/preachings/teachings, worship, ushering, 'Bible' studies those of us who conduct these activities labor in vain... Unless the Lord is in our careers, our Mondays to Fridays, our night shifts/weekend shifts...our overtimes/extra time are done in vain. We may sense some kind of success or accomplishments as we do these, but if the Lord isn't there then it's all in vain.

That said, how do we then know if the Lord is in it? When the Lord is in it you definitely KNOW He is in it and you won't need to be told that He's in it (at least in most cases). But when He isn't in it I can try to point out few telling signs; you start to feel like doing these things as if they were chores, you start to become too 'accustomed' to the duty of preaching/worshipping(just examples). It's as if the way sometimes I drove to/from work, I came to know my way too much so much that sometimes I found myself home without having really understood how I got there, I was driving but I became super used to my way home...maybe sometime we lead worship only through our beautiful voice and having known the song, but maybe not being in the worship itself.

Let me stop there for now... Whatever we do, however we do it, wheresoever we do it may we always throw up our arms in the air and say Lord lead the way. Even for the activities that we feel very gifted in, those(gifts) tend to be the ones which mislead us into thinking that as for that particular gift I need not bother God to lead me, I know my way home," may your prayers, may my prayers always be to ask God to lead the way.