Matthew 7:21: "Not everyone who says to me 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven."
Will (2307 Greek - Strong's Exhaustive Concordance): thelema (thel-ay-mah): desire, pleasure, will.
I was recently reminded of this verse during a Bible study. To be honest, a knot formed in my stomach as I read it. I questioned whether or not I was truly doing the will of the Father.
In order for me to understand the context of this verse, I read the verses before and after verse 21.
Verse 20: "Thus, by their fruit you will recognize them."
Verses 22 and 23: "Many will say to me on that day, 'Lord, Lord, did we not prophesy in your name, and in your name drive out demons and perform many miracles?' 23 Then I will tell them plainly, 'I never knew you. Away from me, you evildoers!'"
I believe Jesus is referring to those who "talk the talk," but don't walk with Him. They are doing their own wills, their own desires, not the will of the Father. Their fruit is rotten.
So, what is the Father's will? In John 6:40, Jesus says: "For my Father's will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise him up at the last day." It's God's desire or pleasure for us to believe in His Son and to spend eternity with Him. What a great verse! More proof as to how much the Father loves us.
This particular definition of "will" is also used in other places. The first mention of it is in the Lord's Prayer: "...Your kingdom come, your will be done on earth as it is in heaven." (Matthew 6:10).
Jesus used "will" during his prayer in the Garden of Gethsemane: "My Father, if it is not possible for this cup to be taken away unless I drink it, may your will be done."
Again in both of these verses, Jesus is referencing the Father's will, not ours, or Jesus' will.
Another point I find interesting is whenever Jesus spoke of God's will, he used "Father" instead of "God" or "Lord." It adds a degree of parent-child intimacy (obviously, since Jesus is the Son of God), but for me as well. It adds a sense of wanting to do the Father's will, since I am His child wanting to please and obey Him.
Now I use Matthew 7:21 as a spiritual check. Am I doing the Father's will or mine? To do the Father's will is to say so long to my will, my desire. At times, it will be a sacrifice to me, but it's a choice I make, just like Jesus made his choice to die for our sins. If the Father's will is important enough for Jesus to follow it to the point of death, then, as his disciple, I need to follow his example.