There is a lot of sentiment that refutes eternal security based on the belief that it propagates freely sinning.
The Bible teaches both eternal security and living righteously.
Let's first look at eternal security.
[Jhn 3:14-16 KJV] 14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up: 15 That whosoever believeth in him should not perish, but have eternal life. 16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
While the Old Testament was primarily given to Israel to obey, we can still learn from it.
The Jews only had to believe on Jesus to have eternal life.
[Rom 3:21-22 KJV] 21 But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets; 22 Even the righteousness of God [which is] by faith of Jesus Christ unto all and upon all them that believe: for there is no difference:
Now on to Paul who was given revelation from the risen Christ Jesus to preach our gospel today for Jew and Gentile.
Paul revealed that we have the righteousness of God by faith in Christ. If have been declared righteous then we can know we have eternal security.
[Rom 4:21-25 KJV] 21 And being fully persuaded that, what he had promised, he was able also to perform. 22 And therefore it was imputed to him for righteousness. 23 Now it was not written for his sake alone, that it was imputed to him; 24 But for us also, to whom it shall be imputed, if we believe on him that raised up Jesus our Lord from the dead; 25 Who was delivered for our offences, and was raised again for our justification.
Righteousness was imputed to Abraham; it was not his righteousness but the righteousness of God.
The righteousness of Christ is imputed to us as well.
Jesus died for our sins and rose for our justification unto eternal life.
[Rom 5:9-11 KJV] 9 Much more then, being now justified by his blood, we shall be saved from wrath through him. 10 For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. 11 And not only [so], but we also joy in God through our Lord Jesus Christ, by whom we have now received the atonement.
We are justified by his blood and are reconciled.
[Rom 5:21 KJV] 21 That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord.
[Rom 6:23 KJV] 23 For the wages of sin [is] death; but the gift of God [is] eternal life through Jesus Christ our Lord.
[Tit 1:2 KJV] 2 In hope of eternal life, which God, that cannot lie, promised before the world began;
[Tit 3:7 KJV] 7 That being justified by his grace, we should be made heirs according to the hope of eternal life.
These verses promise eternal life and security.
Being justified can we freely sin?
[Rom 6:1-2 KJV] 1 What shall we say then? Shall we continue in sin, that grace may abound? 2 God forbid. How shall we, that are dead to sin, live any longer therein?
Paul gives answer to those who would say we are free to sin.
[Rom 6:6-7 KJV] 6 Knowing this, that our old man is crucified with [him], that the body of sin might be destroyed, that henceforth we should not serve sin. 7 For he that is dead is freed from sin.
We are to reckon we are dead to sin but alive to God.
[Rom 6:12, 14-15, 22 KJV] 12 Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof. ... 14 For sin shall not have dominion over you: for ye are not under the law, but under grace. 15 What then? shall we sin, because we are not under the law, but under grace? God forbid. ... 22 But now being made free from sin, and become servants to God, ye have your fruit unto holiness, and the end everlasting life.
Above are more verses pertaining to sin.
[Tit 2:11-12 KJV] 11 For the grace of God that bringeth salvation hath appeared to all men, 12 Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world;
Finaly the above passage dispels the assertion that being justified eternally by grace promotes sin.