"For He says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” So then it does not depend on the man who wills or the man who runs, but on God who has mercy." Romans 9:15-16
For a long time I thought that I was saved because I chose to accept Jesus as my Savior. Thus my salvation was mine, I earned it. With Paul's help here and other places, I see that I had nothing to do with it. God chose me. He prepared the way for my salvation by sending His Son, Jesus to die for my sins. He paid the cost. Then He pursued me, chased me down and cast His mercy on me. The end result is that I had only to accept what He had already done for me.
Let me paint a word picture for you. Let's say I receive a letter in the mail saying I had won a new top-of-the-line pickup truck. All I have to do is return the postage paid card accepting it and it will be delivered to my door.
OK, I drop the card in the mailbox. Now the question: did I earn the truck? Obviously not. I did not pay for it. I did not build it. I did not pay the postage on the card. I did not even ask for it. All I did was return a card. I didn't even have to drive to the dealer to pick it up! That new truck in my driveway is mine because someone else chose to pay the cost for it to be delivered to my door.
That's the way it is with God's mercy and His salvation. We haven't earned it. It is free. All we have to do is accept what God has already done! Do we have an AWESOME God or what? Hallelujah, Amen.