Once you're saved, you're always saved. That's a popular belief, but does it match up with what God says? I think not so much, although the caveat is that we are being saved—an ongoing process wherein we "grow in respect to salvation." (1 Peter 2:2) Can a person fall from grace? Let's look at some points.
1.) Gal 5:4 You who are trying to be justified by the law have been alienated from Christ; you have fallen away from grace.
2.) 2 Pe 1:10 Therefore, brothers, be all the more diligent to confirm your calling and election, for if you practice these qualities you will never fall.
3.) 2 Pe 2:20 For if, after they have escaped the defilements of the world by the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and are overcome, the last state has become worse for them than the first.
4.) 1 Pe 5:8 Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour.
5.) Heb 3:12 Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.
God gives us those admonitions so that we will live faithfully and end with a fierce finish. Let's not be like Solomon, the wisest ever, who fell away.