The cross of Jesus Christ is a magnet for souls. Everyone knows that positive and negative attract, so the positive in this case is the cross and the negative are God's elect. By God's sovereign will he draws us to the center of human history, which is the cross. Through this process we rebel against God and try to fight his pull on our hearts, but God's pursuit of his bride is in his sovereign hands and he will not and cannot fall short.
We fail to see the glory of the cross at times, and turn from it and act like it never happen so then we can go on sinning. But if the cross is at the forefront of our minds then why would we ever want to sin. At that moment, we see our Savior bearing our pain and suffering, we see our hope for eternal joy. Let's not forget about the resurrection though. Through that we now have a living Savior who is interceding for us, sin and death have no power over us anymore, Jesus has made a way to get to his Father. As Christians this is what we should be looking towards, running towards, and building our lives around. In 1 Corinthians 15 Paul talks about the Resurrection of the dead. If Christ wasn't raised from the dead then our faith is in vain, but since he has been raised from the dead it proves that he is God and our work , if done for God, is not done in vain.
Back to the magnet analogy... Once we get to the cross and surrender ourselves through faith, the "positive" charge of Christ (his righteousness) is imputed to us and we have a new charge (identity). Now in one sense we have the same charge as Christ, so we take the good news of salvation we have received, and pursue the other negative charged elect that have yet to hear of the gospel. In another sense we still have a negative charge of our own, and need to continually be brought back to the cross ourselves. Basically justification and sanctification. We are fully given a positive charge (100% righteous), but we still have a negative charge as well (because of our depravity we won't be fully glorified until we reach heaven).
I know it's not a perfect analogy but the main thing I'm trying to say is that God calls people and grants us the grace to put saving faith in his perfect Son, and from the love, grace, and mercy that was shown to us we should be compelled to share it will others. That's the basis of the analogy. It's just a way to show God as the Good Shepherd of his sheep and the Bridegroom of his church.