As a believer, you should deny anyone who teaches you that
“Christ nowhere prayed for an unfailing perseverance of believers in faith.”
A teaching from the Canon of Dordt speaks to this.
For they contradict Christ himself when he says: I have prayed for you, Peter, that your faith may not fail (Luke 22:32); and John the gospel writer when he testifies in John 17 that it was not only for the apostles, but also for all those who were to believe by their message that Christ prayed: Holy Father, preserve them in your name (v. 11); and My prayer is not that you take them out of the world, but that you preserve them from the evil one (v. 15).
John 17:11 And I am no longer in the world, but they are in the world, and I am coming to you. Holy Father, keep them in your name, which you have given me, that they may be one, even as we are one.
John 17:14 I have given them your word, and the world has hated them because they are not of the world, just as I am not of the world.
John 17:15 I do not ask that you take them out of the world, but that you keep them from the evil one.
John 17:16 They are not of the world, just as I am not of the world.
John 17:17 Sanctify them in the truth; your word is truth.
John 17:18 As you sent me into the world, so I have sent them into the world.
John 17:19 And for their sake I consecrate myself, that they also may be sanctified in truth.
Be encouraged friends Christ prays for you