The message of grace is not a double message.
Well, I believe in God's grace according to the Bible just fine. I just do not think the OSAS version or the Belief Alone version of God's grace is even remotely biblical and or moral (or good). The Bible's version of God's grace does not teach a double message because it says the grace of God teaches us to deny ungodliness and that we should live godly and righteously in this present world (See Titus 2:11-12). 1 John 1:7 says that if we walk in the light as He is in the light, the blood of Jesus Christ cleanses us from all sin. Walking in the light is loving your brother (1 John 2:9-10). One way to love your neighbor (brother) is the equivalent of keeping the Moral Law (like: Do not murder, do not steal, and do not covet, etc. - See: Romans 13:8-10). Hebrews 5:9 essentially says that Christ is the author of eternal salvation to all who OBEY Him. Hebrews 12:14 says without holiness, no man shall see the Lord. When certain believers faced Christ (Who did works in Christ's name) they were told to depart from Christ because they worked iniquity (sin) (See Matthew 7:23). We know that the unprofitable servant is cast into outer darkness (Matthew 25:30). But in the Eternal Security (OSAS or Once Saved Always Saved) camp, you can sin and still be saved; Yet, they also say that believers are to live holy. Yet, they also say they are always in some kind of sin of some kind according to a false interpretation on 1 John 1:8, and other verses. So the OSAS Proponent preaches a double message. For I have yet to encounter an OSAS Proponent who says that King David was not saved while committing his sins of adultery and murder.
You said:
Salvation must be by grace, not by what we do or do not do, for we all can not live up to the requirement of the law. It must be by grace so it is sure to all seed, there are no maybes with salvation, the message is sure, fixed, immovable, while we trust in Christ to justify us we are justified.
Rom 4:15-16 For the law brings wrath, but where there is no law there is no transgression. That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his offspring—not only to the adherent of the law but also to the one who shares the faith of Abraham, who is the father of us all,
Sorry. That is not how salvation works. In fact, unless you are a Calvinist, you believe that you had to do something to be saved. You believe that you had to receive (take action) by seeking the Lord's forgiveness over your sin. If a person did not partake in this one action or decision, then you believe that a person is not saved. They need to act so as to receive Christ for salvation.
As for Romans 4:15-16:
Paul is fighting against "Circumcision Salvationism" (Which was a form of Circumcision Salvationism that did not even apply in the Old Testament). Jews were trying to convince certain believers that they needed to be circumcised to be initially saved. But not even the Old Covenant taught that you first needed to be circumiced to be saved (See Romans 4:9-12). Abraham had to FIRST believe God in order to be saved. But this did not negate the fact that circumcision (ONLY under the Old Covenant when it was in effect at one time in the past) was also necessary for salvation (See Genesis 17:14). Abraham had to later be circumcised to be saved or he would have broke God's covenant.
Under the New Covenant or New Testament, we are not commanded to be circumcised. Jesus and His followers did not give us any command to be circumcised. This is why you will read Paul say things like, "What profit is there of circumcision?" (Romans 3:1). It's why he says, But neither Titus, who was with me, being a Greek, was compelled to be circumcised:” (Galatians 2:3). It's why Paul said, "...if ye be circumcised, Christ shall profit you nothing." (Galatians 5:2). In fact, this matter is even more cleared up if you were to read the following words by the Jerusalem counsel. For they addressed the heresy of "Circumcision Salvationism."
- Acts of the Apostles 15:1 says, “And certain men which came down from Judaea taught the brethren, and said, Except ye be circumcised after the manner of Moses, ye cannot be saved.”
- Acts of the Apostles 15:5 says, But there rose up certain of the sect of the Pharisees which believed, saying, That it was needful to circumcise them, and to command them to keep the law of Moses.”
- Acts of the Apostles 15:24 says, “Forasmuch as we have heard, that certain which went out from us have troubled you with words, subverting your souls, saying, Ye must be circumcised, and keep the law: to whom we gave no such commandment:”
You said:
But sin brings about death, if we persist in sin, not heeding the Spirit, we will eventually slip away from grace. Grace is like swimming, while we have it we keep our heads above the waves of eternal death. Sin is like adding weights to us, it begins to make us sink. If we do not remove the sin, it may well make us drown.
If sin can drag you down, and make you drown (implying spiritual death) then it is not by the OSAS version of God's grace. You have to do something to remove sin from your life so you don't drown. This is why the OSAS message that you are saying here is preaching a double message. On the one hand you say that it is solely by God's grace and yet you contradict yourself and say that you must remove sin otherwise that person can drown.