No. If your salvation depended on your grip, you could lose it any day. But it depends on His, and He has promised you will never perish. You are held, not on probation.
The Grace Answer
Almost everyone who asks this question is already trying hard to hold on. That is the tell. The fear assumes that staying saved is a grip you maintain, and that on a bad enough day your fingers might slip. But Scripture never once puts your salvation in your hands.
Jesus said it plainly about His own sheep: “I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand.” Notice who is doing the holding. Not you. Him. And notice the kind of life He gives. If eternal life could be lost, it was never eternal to begin with. It would just be temporary life on a renewable contract, and that is not what He offered.
The moment you believed, something permanent happened. You were sealed with the Holy Spirit, who Paul calls the guarantee of our inheritance. A seal is a mark of ownership and a promise of delivery. God is not in the habit of breaking His guarantees.
But what about the warning passages?
Hebrews 6 and Hebrews 10 frighten a lot of people, because they sound like the door could still close. Read in context, those warnings are aimed at people tempted to walk away from Christ entirely and go back to the old covenant system of sacrifices, as if the cross never happened. The warning is against abandoning the only thing that saves, not against a believer who sinned and feels ashamed. Struggling with sin is not the same as renouncing the Savior.
Your security was never meant to rest on the quality of your week. It rests on the finished work of Christ and the faithfulness of God. Paul was persuaded that nothing in all creation could separate us from the love of God in Christ. Notice he did not add an asterisk for your worst moment. You are not one failure away from being cast out. You are His, and He intends to keep what He bought.