We can self assure that "we are saved" all we want. Jesus may have different idea about us.
You know Jesus says not everyone who says "Lord, Lord will not inherit God's kingdom".
the way are you reading them do not harmonize with Jesus' direct word.
If ever a person gets off track they need to go back to what Jesus said, what HE taught. Have you ever heard about what is called, false conversions? When a person is not truly saved but has come to believe that they are saved, through some method, way, or conversion process of some sort? A person can be saved by praying a sinners prayer. What if they prayed a prayer but they were not thereby saved?
So we need sound doctrine, and Jesus' word is where to start / begin.
1 Timothy 4:6 NASB - 6 In pointing out these things to the brethren, you will be a good servant of Christ Jesus, constantly nourished on the words of the faith and of the sound doctrine which you have been following.
2 Timothy 4:3 NASB - 3 For the time will come when they will not endure sound doctrine; but wanting to have their ears tickled, they will accumulate for themselves teachers in accordance to their own desires,
Titus 1:9 NASB - 9 holding fast the faithful word which is in accordance with the teaching, so that he will be able both to exhort in sound doctrine and to refute those who contradict.
Titus 2:1 NASB - 1 But as for you, speak the things which are fitting for sound doctrine.
1 Timothy 6:3 NASB - 3 If anyone advocates a different doctrine and does not agree with sound words, those of our Lord Jesus Christ, and with the doctrine conforming to godliness,