Other Passages of Scripture Which the Pelagians Abuse
Then, again, there is the Scripture contained in the second book of the Chronicles: “The Lord is with you when you are with Him: and if you shall seek Him you shall find Him; but if you forsake Him, He also will forsake you.” This passage, no doubt, clearly manifests the choice of the will. But they who maintain that God's grace is given according to our merits, receive these testimonies of Scripture in such a manner as to believe that our merit lies in the circumstance of our “being with God,” while His grace is given according to this merit, so that He too may be with us.
In like manner, that our merit lies in the fact of “our seeking God,” and then His grace is given according to this merit, in order that we may find Him. Again, there is a passage in the first book of the same Chronicles which declares the choice of the will: “And you, Solomon, my son, know the God of your father, and serve Him with a perfect heart and with a willing mind, for the Lord searches all hearts, and understands all the imaginations of the thoughts; if you seek Him, He will be found of you; but if you forsake Him, He will cast you off for ever.” But these people find some room for human merit in the clause, “If you seek Him,” and then the grace is thought to be given according to this merit in what is said in the ensuing words, “He will be found of you.”
And so they labour with all their might to show that God's grace is given according to our merits,— in other words, that grace is not grace. For, as the apostle most expressly says, to them who receive reward according to merit “the recompense is not reckoned of grace but of debt.”
Source: On Grace and Free Will (New Advent)