If you have been a Christian for a good while, you can probably think of times when the Holy Spirit really impressed upon your heart to say something or do something specific. Years ago, I think not long after we had our first child, we were going through a pretty difficult time financially. I cannot even remember the specifics - it might have been a large repair bill for our car at the time - but I know we hadn't told anyone about our financial worry. I do remember thinking, "How in the world will we pay this?" And I remember the day that a letter and a check arrived in the mail from my Grandma. (I wish I knew where that letter was!) She had written us a check for a generous amount of money (I don't even remember the sum) and had written something like the following: The Lord placed you on my heart and I knew I needed to do this. I've learned that whenever He tells me to do something, I need to do it right away.
That money met our need; but, more importantly, the valuable lesson I learned from her that day still sticks with me. When the Holy Spirit tells you to do something, do it! If the Lord lays something specific on your heart, follow through!
I can think of times when I have obeyed the Spirit's leading to do something specific for a friend or even a stranger. Immediately, I felt peace and joy that come from obedience. Shamefully, I can also think of times when I second-guessed whether that was really the Holy Spirit prompting me, wondered how I would do that, or made an excuse. Immediately, I felt convicted and knew I had robbed myself of a blessing after the opportunity had passed.
Walking in the Spirit (or being in the "measure of the fullness of Christ" as Beth Moore puts it) is a daily choice. Very simply put, reading His Word, praying, and saying "no" to sin and "yes" to His ways allow us to be filled with His Spirit. And being filled with His Spirit puts us in a position where we can be fully used by Him! Don't you want that?
For your viewing enjoyment (and for a blessing!) I downloaded a rather humorous story that Beth Moore tells about this very thing. :)