The men said to her, “We shall be free from this oath to you which you have made us swear, unless, when we come into the land, you tie this cord of scarlet thread in the window through which you let us down, and gather to yourself into the house your father and your mother and your brothers and all your father’s household." vs17-18 We must be in the house to be saved. That house is Christ.
First, Christ is the safety of all believers. He's the only refuge we have. Colossians 1:22-23," But now He has reconciled you by His physical body through His death, to present you holy, faultless, and blameless before Him— if indeed you remain grounded and steadfast in the faith and are not shifted away from the hope of the gospel that you heard. This gospel has been proclaimed in all creation under heaven, and I, Paul, have become a servant of it." There's no other security from God's wrath, and we must stay in Christ. We can't go out. We can't believe any other message. Christ must be all.
He's the fullness of the Godhead bodily, and we're complete in Him [Col 2:9-10]. God's given Christ preeminence in every sermon, and He's glorified through the Son. Without Christ, the Spirit will not work. His job is to fix our eyes upon Christ, in whom are all the riches of the gospel. Colossians 2:3, "All the treasures of wisdom and knowledge are hidden in Him."
Secondly, if you want holiness, then look to Christ. Sinners leave the gospel, because they want their own goodness, so they get deceived by their own strength and beguiled into human wisdom. They leave the SIMPLICITY OF THE GOSPEL for "higher methods" and "practical sermons." They don't know that Satan has beguiled them from the Beloved [Col 2:8].
Look to Christ, and He'll heal your sins. Follow Christ, and He'll show you how to walk. Every doctrine has its life in Christ, or Christianity is a wilderness of "touch not, taste not, handle not [Col 2:21]." Don't be foolish and turn from the gospel.
Thirdly, if you leave the gospel, then your blood is on your own head. Joshua 2:19, "If anyone goes out the doors of your house, his blood will be on his own head, and we will be innocent. But if anyone with you in the house should be harmed, his blood will be on our heads." It's YOUR OWN fault if you perish! There's no lack of grace in God.
Because of the blood, God will give you holiness and power over sin. He'll walk with us as a loving, helping Father, so we can be recovered and strengthened. He'll delight to cleanse you, and receive you in repentance. He'll teach you!
Take away the blood, however, and He's an avenging God, never satisfied with man. Take away our completeness in Christ, and He'll never help us nor be appeased. He'll meet us as an angry lion or a bear robbed of her cubs, if we don't stay in Christ. He'll chasten us and bring us back, or He'll damn us forever as bastards and hypocrites. Hebrews 12:8, "But if you are without discipline—which all receive—then you are illegitimate children and not sons."
Do not play with God! As gracious as He is, it's all in Christ. Preaching is preaching Christ, or it's powerless to save, transform, and keep us in thanksgiving. It's Christ or nothing! Colossians 2:6-7," Therefore, as you have received Christ Jesus the Lord, walk in Him, rooted and built up in Him and established in the faith, just as you were taught, overflowing with gratitude."
Finally, stay in the house. Don't go away!