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In the Name of the Father, and (+) of the Son, and of the Holy Spirit. Amen.
1 John 1:5-9
5 This is the message we have heard from him and proclaim to you, that God is light, and in him is no darkness at all. 6 If we say we have fellowship with him while we walk in darkness, we lie and do not practice the truth. 7 But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. 8 If we say we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. 10 If we say we have not sinned, we make him a liar, and his word is not in us.
Devotion from the Blessed Dr. Martin Chemnitz
I chose this section of Chemnitz on the difference between mortal and venial sins because I think it is extremely important and valuable for the life of the Christian to properly understand what he explains here.
203 Do the Remains of Sin Exist and Remain in the Reborn in This Life?
They by all means are and remain. For though [the reborn] are ruled by the Holy Spirit, yet they complain that nothing good dwells in their flesh, in fact also when they want to do good, evil is connected [with it] (Ro 7:18, 21), and that the flesh wars against the Spirit (Gl 5:17). And even also when they are holy and serve God and are not conscious of any evil, yet they confess that they are sinners. 1 Co 4:4; Ps 32:6; 130:3; 143:3. In fact, he that does not acknowledge and confess this, but says that he has no sin, deceives himself. 1 Jn 1:8. Therefore all the saints have need in this life daily to repeat this: Father, forgive us our sins.
204 Is Then David, Committing Adultery, Nevertheless Righteous and Holy, and Does He Remain So?
By no means. For Scriptures distinguishes between sins, namely that in the saints or reborn there are some sins because of which they are not condemned, but at the same time retain faith, the Holy Spirit, grace, and the forgiveness of sins. Ro 7:23–8:1; 1 Jn 1:8–9; Ps 32:1. But Scripture testifies that there are also some other sins in which also the reconciled, when they have fallen, lose faith, the Holy Spirit, the grace of God, and life eternal, and render themselves subject to divine wrath and eternal death unless, turned again, they are reconciled to God through faith. Ro 8:13; 1 Co 6:10; Gl 5:21; Eph 5:5; Cl 3:6; 1 Jn 3:6, 8; 1 Ti 1:19; 2 Ptr 1:9; And the useful distinction between mortal and venial sin is drawn from this basis. Paul speaks of sin ruling against conscience or with conscience put away, and sin that indeed dwells in the flesh but does not rule. 1 Ti 1:19; Ro 6:12, 14; 7:17.
205 What is the Use of Retaining and Earnestly Inculcating This Difference Between Mortal and Venial Sin in the Church?
I. That we might learn to acknowledge and earnestly avoid mortal sins.
II. If we are caught in that kind of sins, that we do not obstinately persevere and continue in them impenitently.
III. That we try the more to restrain and control sin that dwells in us, lest it become mortal. For, when this distinction is neglected or not rightly understood and used, Christians also often fall into security and impenitence. Pastors are therefore to be reminded and trained in examinations not only to list the 7 mortal (or deadly, capital) sins, but to be able to point out to their hearers, in each Commandment, which sins are mortal, which venial.
Let definitions as to what is venial sin, what mortal sin, be sought from Philipp [Melanchthon’s] examination and for the sake of declaration be added to these questions.
206 Is, Then, Original Sin, Which Still Remains in the Reborn in This Life, in Itself Such a Light Little Sin, or, So to Say, Peccadillo, that God Neither Can Nor Wants to Be Angry Against It?
All sins are not equal; some are more grievous and greater than others (Jn 19:11; Mt 11:22; Lk 12:47–48); yet if one judges according to the sense of the divine law, no sin per se and by its own nature deserves forgiveness; that is, none is so small and insignificant, but that it makes [one] subject to divine wrath and worthy of eternal damnation if God enters into judgment with him. Dt 27:26; Gl 3:10; Ja 2:10. This error regarding the least commandment of the divine law is condemned by Christ in the Pharisees. Mt 5:19. Paul sadly complains also about sin still dwelling in his flesh. Ro 7:24; Gl 5:17.
207 Are Some Sins So Great and Horrible that They Cannot Be Forgiven in the Gospel to Those Who Repent and Believe in Christ?
No. Christ made satisfaction for all sins. 1 Jn 2:2. He wants to save also the greatest sinners. 1 Ti 1:15. He commanded repentance and remission of sins to be preached in His name to all sinners. Jn 20:23; Mt 9:13; Lk 15:7; 24:47. Grace abounded more than sin. Ro 5:20.
208 Now, Then, Since It is Clear that No Sin Per Se Deserves Forgiveness, Likewise that No Sin is So Horrible that It Cannot Be Forgiven to Those Who Repent and Believe in Christ—Why, Then, are Some Sins in the Reborn Called Venial, Some Mortal?
This should be well and carefully explained, so that each Christian can know and determine if he is living in mortal or venial sin. The explanation consists essentially in this, that everyone examine himself as to whether or not he has true repentance and faith. Ro 2:4–5; Jer 5:3; 2 Co 13:5. Original sin, which still dwells in the flesh of the reborn, is not idle, but is the restless law of sin in our members, enticing, tempting, driving to sin with various suggestions and evil lusts. Ja 1:14; Ro 7:8; Gl 5:17. Since, then, one who is reborn does not delight in this kind of carnal lusts, and is neither led by them nor follows [them], but earnestly represses and crucifies them as sins and mortifies [them] through the Spirit, lest they rule or be performed (Ro 6:12; 7:15; 8:13; Gl 5:24), this very thing is a very sure sign of true and earnest repentance. And when the reborn pray that God would not impute these weaknesses to them but forgive for the sake of Christ, and at the same time believe and trust that Christ, as the true propitiation, would, in the sight of God, cover this their uncleanness with His innocence and obedience (Ro 4:7; Ps 32:1; 1 Jn 1:7; 2:1–2), this also is a sure sign of true and justifying faith. And where true faith, in earnest repentance, apprehends Christ in the Gospel, and relies on Him and is supported [by Him], there is no condemnation, but the pure grace of God, forgiveness of sins, and eternal salvation (Ro 8:1; 1 Jn 1:9; Ps 32:2). In this way there are and occur these venial sins in the reborn, for which they are not condemned, because, as Augustine says, they live under grace.
209 But What If We Indulge and Delight in Evil Lusts and Seek Occasions to Give Them Free Rein (Ro 6:12; MI 2:1; Ja 1:15)?
Then they become mortal sins (Ro 8:13; Ja 1:15), because there surely is no room for true repentance and faith where the lusts of the flesh are served and given rein, so that they break out into action. 1 Ti 1:19; 5:8; 2 Ptr 1:9. It is the nature and particular character of true faith that it does not seek how to commit, continue, and heap up sins freely, but rather hungers and thirsts after the righteousness that releases and frees from sins. Therefore, where there is no true repentance, the Holy Spirit pronounces a very solemn sentence. Jer 5:3, 9; Ro 2:5, 9; Lk 13:3; Rv 2:5. And where there is no true faith, there is neither Christ, nor the Holy Spirit, nor the grace of God, nor forgiveness of sins, nor any salvation. Therefore what? Doubtless the wrath of God, death, and eternal condemnation, unless the fallen are turned to God again. Cl 3:6; Ro 8:13. As a result of this, therefore, and for this reason mortal sins occur in the reborn, namely when repentance, faith, Christ, and the Holy Spirit are driven out and lost.
210 How, Then, Should One Deal with Those Who Have Fallen into This Kind of Sins?
Their sins are not to be disguised by silence, camouflaged, excused, or defended, but solemnly and earnestly censured and rebuked. Is 56:10; 58:1; Eze 13:10, 18; 2 Ti 4:2; Tts 1:13: “Reprove them sharply,” in such a way that the fearful judgment of God is threatened on them; 1 Co 6:10; Gl 5:21; Cl 3:6; 1 Jn 3:15; Mt 11:21; 2 Ptr 2:10. For he that regards those people as true Christians, and charms and misrepresents them, not only miserably misleads them, but also makes himself partaker of their damnation. Is 3:12; Jer 8:11; 23:17; Eze 3:18; 33:8.
Now, the preaching of repentance, rebuking sins, is the instrument and means by which God wants to lead fallen sinners back to the way and convert them. Jer 26:2–3. But if the wicked, neglecting this means, will persevere and continue in his wickedness, he indeed shall perish, but the word of the minister shall deliver his soul. Eze 3:19.
211 But What If the Fallen Rise Again by the Grace of God and Earnestly Repent?
Then they are indeed to be received with joy and are to be restored and supported with the declaration of the forgiveness of sins. Jer 3:12; 18:8; Eze 18:21; 33:15; Mt 18:13, 27; Lk 15:7. This is what the examples of Scripture testify, e.g., Peter, David, the prodigal, the Corinthians and Galatians. And this indeed not only seven times, but seventy times seven times, Mt 18:22.
Lord God, heavenly Father, who by Your Son has revealed to us that heaven and earth shall pass away, that our bodies shall rise again, and that we all shall appear before the judgment seat: We beseech You, keep us by Your Holy Spirit in Your word; establish us in the true faith, graciously defend us from sin and preserve us in all temptations, that our hearts may not be overcharged with gluttony and drunkenness, and cares of this life, but that we may ever watch and pray and, trusting fully in Your grace, await with joy the glorious coming of Your Son, and at last obtain eternal salvation, through Your beloved Son, Jesus Christ our Lord, who lives and reigns with You and the Holy Spirit, one true God, world without end. Amen.
 Chemnitz, M., & Poellot, L. (1999). Ministry, word, and sacraments: an enchiridion (electronic ed., pp. 102–105). St. Louis: Concordia Publishing House.
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