No, not and commit a sin unto death, unfortunantly, the devil is a thorn in the flesh that will buffet all of God's children until we die, but we shall never fall from Grace and commit a sin unto death, we is kept by the power of God. We all sin, which is of the devil but its not sins such as killing, adultery, stealing etc. Our tongues gets us into trouble a lot. We fail to do what we should a lot. We are none perfect, but we do not fall from Grace into sins unto death. We have the "indwelling of the Holy Spirit" and the "mind of Christ" of which David did not. There were times God was not pleased with David.
I believe in once saved always saved Charles.
1Cr 1:8Who shall also confirm you unto the end, [that ye may be] blameless in the day of our Lord Jesus Christ.
1Th 5:23¶And the very God of peace sanctify you wholly; and [I pray God] your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
1Th 5:24Faithful [is] he that calleth you, who also will do [it].
Eph 4:30And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption.
Jud 1:24¶Now unto him that is able to keep you from falling, and to present [you] faultless before the presence of his glory with exceeding joy,
Jud 1:25To the only wise God our Saviour, [be] glory and majesty, dominion and power, both now and ever. Amen.