The efficient CAUSE of conversion is both internal and external.

[1] The INTERNAL cause is free grace alone. 'Not by works of righteousness which we have done—but of his mercy he saved us', and 'by the renewing of the Holy Spirit' (Titus 3:5). 'Of his own will he begat us' (James 1:18). We are chosen and called unto sanctification, not for it (Eph 1:4).

God finds nothing in man to turn His heart—but enough to turn His stomach; He finds enough to provoke His loathing—but nothing to excite His love. Look back upon yourself, O Christian! Reflect upon your swinish nature, your filthy swill, your once beloved mire (2 Pet 2). Behold your slime and corruption. Do not your own clothes abhor you? (Job 9:31). How then should holiness and purity love you? Be astonished, O heavens, at this; be moved, O earth. Who but must needs cry, Grace! Grace! (Zech 4:7). Hear and blush, you children of the Most High God. O unthankful men, that free grace is no more in your mouths, in your thoughts; no more adored, admired and commended by such as you! One would think you should be doing nothing but praising and admiring God wherever you are. How can you forget such grace, or pass it over with a slight and formal mention? What but free grace could move God to love you, unless enmity could do it, unless deformity could do it? How affectionately Peter lifts up his hands, 'Blessed be the God and Father of our Lord Jesus, who in his abundant mercy has begotten us again.' [1 Pet 1:3] How feelingly does Paul magnify the free mercy of God in it, 'God who is rich in mercy, for his great love wherewith he loved us, has quickened us together with Christ. By grace are you saved' (Eph 2:4-5)!

[2] The EXTERNAL cause is the merit and intercession of the blessed Jesus. He has obtained gifts for the rebellious (Psalm 68:18), and through Him it is that God works in us that which is well-pleasing in His sight (Heb 13:21). Through Him are all spiritual blessings bestowed upon us in heavenly places (Eph 1:3). He intercedes for the elect that believe not (John 17:20). Every convert is the fruit of His travail. Never was an infant born into the world with that difficulty which Christ endured for us. All the pains that He suffered on the cross were our birth-pains. He is made sanctification to us (1 Cor 1:30). He sanctified Himself, that is, set apart Himself as a sacrifice, that we might be sanctified (John 17:19). We are sanctified through the offering of His body once for all (Heb 10:10).

It is nothing, then, but the merit and intercession of Christ, that prevails with God to bestow on us converting grace. If you are a new creature, you know to whom you owe it; to Christ's pangs and prayers. The foal does not more naturally run after the dam, nor the suckling to the bosom, than a believer to Jesus Christ. And where else should you go? If any in the world can show for your heart what Christ can, let them do it. Does Satan claim you? Does the world court you? Does sin sue for your heart? Why, were these crucified for you? O Christian, love and serve your Lord while you have a being.