William Guthrie's The Christian's Great Interest concludes with the following:
Conclusion--The whole Treatise resumed in a Few Questions and AnswersQuest. 1. What is the great business a man has to do in this world?
Ans. To make sure a saving interest in Christ Jesus, and to walk suitably thereto.
Q. 2. Have not all the members of the visible church a saving interest in Christ?
A. No, verily; yea, but a very few of them have it.
Q. 3. How shall I know if I have a saving interest in Him?
A. Ordinarily the Lord prepareth His own way in the soul by a work of humiliation, and discovereth a man's sin and misery to him, and exerciseth Him so therewith, that He longs for the physician Christ Jesus.
Q. 4. How shall I know if I have got a competent discovery of my sin and misery?
A. A competent sight of it makes a man take salvation to heart above anything in this world: it maketh him disclaim all relief in himself, seen in his best things: it maketh Christ who is the Redeemer, very precious to the soul: it makes a man stand in awe to sin afterwards, and makes him content to be saved upon any terms God pleases.
Q. 5. By what other ways may I discern a saving interest in him?
A. By the going out of the heart seriously and affectionately towards Him, as He is held out in the gospel; and this is faith or believing.
Q. 6. How shall I know if my heart goes out after Him aright, and that my faith is true saving faith?
A. Where the heart goes out aright after Him in true and saving faith, the soul is pleased with Christ alone above all things, and is pleased with Him in all Him three offices, to rule and instruct as well as to save; and is content to cleave unto Him, whatsoever inconveniences may follow.
Q. 7. What other mark of a saving interest in Christ can you give me?
A. He that is in Christ savingly, is a new creature; He is graciously changed and renewed in some measure, in the whole man, and in all his ways pointing towards all the known commands of God.
Q. 8. What if I find sin now and then prevailing over me?
A. Although every sin deserves everlasting vengeance, yet, if you be afflicted for your failings, confess them with shame of face unto God, resolving to strive against them honestly henceforth, and see unto Christ for pardon, you shall obtain mercy, and your interest stands sure.
Q. 9. What shall the man do who cannot lay claim to Christ Jesus nor any of those marks spoken of it?
A. Let him not take rest until he make sure unto himself a saving interest in Christ.
Q. 10. What way can a man make sure an interest in Christ, who never had a saving interest in Him hitherto?
A. He must take his sins to heart, and his great hazard thereby, and he must take to heart God's offer of pardon and peace through Christ Jesus, and heartily close with God's offer by retaking himself unto Christ, the blessed refuge.
Q. 11. What if my sins be singularly heinous, and great beyond ordinary?
A. Whatsoever thy sins be, if thou wilt close with Christ Jesus by faith, thou shalt never enter into condemnation.
Q. 12. Is faith in Christ only required of men?
A. Faith is the only condition upon which God does offer peace and pardon unto men; but be assured, faith, if it be true and saving, will not be alone in the soul, but will be attended with true repentance, and a thankful study of conformity to God's image.
Q. 13 How shall I be sure that my heart does accept of God's offer, and does close with Christ Jesus? .
A. Go make a covenant expressly, and by word speak the thing unto God.
Q. 14 What way shall I do that?
A. Set apart some portion of time, and, having considered your own lost estate, and the remedy offered by Christ Jesus, work up your heart to be pleased and close with that offer, and say unto God expressly that you do accept of that offer, and of Him to be your God in Christ; and do give up yourself to Him to be saved in His way, without reservation or exception in any case; and that you henceforth will wait for salvation in the way He has appointed.
Q. 15 What if I break with God afterwards?
A. You must resolve in His strength not to break, and watch over your own ways, and put your heart in His hand to keep it and if you break, you must confess it unto God, and judge yourself for it, and flee to the Advocate for pardon, and resolve to do so no more: and this you must do as often as you fail.
Q. 16 How shall I come to full assurance of my interest in Christ, so that it may be beyond controversy?
A. Learn to lay your weight upon the blood of Christ, and study purity and holiness in all manner of conversation: and pray for the witness of God's Spirit to join with the blood and the water; and His testimony added unto these will establish you in the faith of an interest in Christ.
Q. 17. What is the consequence of such closing with God in Christ by heart and mouth?
A. Union and communion with God, all good here and His blessed fellowship in heaven forever afterwards.
Q. 18. What if I slight all these things, and do not lay them to heart to put them in practice?
A. The Lord comes with His angels, in flaming fire, to render vengeance to them who obey not His gospel; and thy judgment shall be greater than that of Sodom and Gomorrah; and so much the greater that thou hast read this Treatise, for it shall be a witness against thee in that day.
Weighty questions indeed. What amazes me about the state of modern evangelicalism is that these types of questions are rarely thought about, let alone asked. And then, if the questions were to be asked, where would the average church goer find answers?
He that is in Christ savingly, is a new creature: Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come. (2 Corinthians 5:17, ESV)