God reveals Himself and His word to man by way of those men who were inspired to write accurately. His words are not joking or misleading. His law is perfect, converting the soul (see quote from the Psalms below).
Many people are uninterested in the word of God and/or unwilling to study it. To those it is worthless. But it is called the 'perfect law of liberty ' by James in the book which bears his name. And Paul refers to it as perfect in 1 Corinthians 13, verses 9 and 10: "For we know in part, and we prophesy in part. But when that which is perfect is come, then that which is in part shall be done away."
Read these inspired descriptions and you may know that the New Testament doctrines are perfect, understandable and within our capabilities of obeying.
But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed. (James 1:25 KJV)
The law of the LORD is perfect, converting the soul: the testimony of the LORD is sure, making wise the simple. (Psalm 19:7 KJV)
"For this commandment which I command you today is not too difficult for you, nor is it out of reach." (Deuteronomy 30:11 NASV)
The perfect law of liberty settled forever in heaven: "Forever, O Lord, Thy word is settled in heaven" (Psalm 119:89).
It makes us free from the burden of sin:
"So shall I keep thy law continually for ever and ever. And I will walk at liberty: for I seek thy precepts." (Psalm 119:44-45).
"You shall know the truth and the truth shall make you free" (John 8:32 KJV).
Its prime interest is for our benefit: "So the Lord commanded us to observe all these statutes, to fear the Lord our God for our good always and for our survival, as it is this day" (Deuteronomy 6:24).
And it furnishes us with all we need to follow Jesus Christ and to teach others:
All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, throughly furnished unto all good works. (2 Timothy 3:17).
According as his divine power hath given unto us all things that pertain unto life and godliness, through the knowledge of him that hath called us to glory and virtue: (2 Peter 1:3 KJV)
Reasons we should devote ourselves to learning and obeying the complete perfect law of liberty:
"For this is the love of God, that we keep His commandments" (1 John 5:3).
If ye love me, keep my commandments. (John 14:15 KJV)
For this is the love of God, that we keep his commandments: and his commandments are not grievous.(1 John 5:3 KJV).
If ye keep my commandments, ye shall abide in my love; even as I have kept my Father's commandments, and abide in his love. (John 15:10 KJV)
Life is short, even at best. If we live to be 100 years old, that is nothing when compared to eternity. All men should be willing to accept the offer extended to them. Jesus warns his followers of the persecutions ahead, in Revelation 2:10:
‘Fear none of those things which thou shalt suffer: behold, the devil shall cast some of you into prison, that ye may be tried; and ye shall have tribulation ten days: be thou faithful unto death, and I will give thee a crown of life.”