All scripture speaks of Christ, if we think we have belief in God, and have eternal life, we wont have that, unless we can understand and acknowledge that all scriptures speak of Christ, of His coming to earth to die and rise aghain for our sins, nobody else has anything worth considering at all, as all else is death and cannot bring life..
John 5:39 Search the scriptures; for in them ye think ye have eternal life: and they are they
which testify of me.
Luke 24:25 Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken:
26 Ought not Christ to have suffered these things, and to enter into his glory?
27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.
To receive the end of our faith, the salvation of our souls, is not by discussing about David or anyone else is it.
It is instead, knowing those prophets ( David etc) who prophesied all their words about Christ, by the Spirit of Christ in them ( is it not sense to know that when the Spirit of Christ is in someone, all they can be speaking of is Jesus Christ, and not their own lives at all ?) to show beforehand of the sufferings of Christ and then His glory.
So through all that, we know no scriptures are of private interpretation, but they all had spoken as they were moved by God, which is impossible to be lamenting over their own lives but can only be for the coming life of Christ in the world.
1 Peter 1:9 Receiving the end of your faith, even the salvation of your souls.
10 Of which salvation the prophets have enquired and searched diligently, who prophesied of the grace that should come unto you:
11 Searching what, or what manner of time the Spirit of Christ which was in them did signify, when it testified beforehand the sufferings of Christ, and the glory that should follow.
2 Peter 1:20 Knowing this first, that no prophecy of the scripture is of any private interpretation.
21 For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost.
Sin, is when we cannot acknowledge the truth. Which is given only by Gods Spirit. ( which the prophets also had, to speak only of Christ, not of themselves.) and they profess God but deny Him in works ( sin of unbelief.)
2 Timothy 2:25 In meekness instructing those that oppose themselves; if God peradventure will give them repentance to the
acknowledging of the
truth;
Titus 1:1 Paul, a servant of God, and an apostle of Jesus Christ, according to the faith of God's elect, and the
acknowledging of the
truth which is after godliness;
Titus 1:16 They profess that they know God; but in
works they
deny him, being abominable, and disobedient, and unto every good work reprobate.