The Bible contains all that we need:
1) to know God,
2) to know God’s will, and
3) to live a life that is pleasing to Him
2 Timothy 3:15–17
15 And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus. 16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: 17 That the man of God may be perfect, throughly furnished unto all good works.
2 Peter 1:3–4
3 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: 4 Whereby are given unto us exceeding great and precious promises: that by these ye might be partakers of the divine nature, having escaped the corruption that is in the world through lust.
Psalm 19:1–14
1 The heavens declare the glory of God; And the firmament sheweth his handywork.
2 Day unto day uttereth speech, And night unto night sheweth knowledge.
3 There is no speech nor language, Where their voice is not heard.
4 Their line is gone out through all the earth, And their words to the end of the world. In them hath he set a tabernacle for the sun,
5 Which is as a bridegroom coming out of his chamber, And rejoiceth as a strong man to run a race.
6 His going forth is from the end of the heaven, And his circuit unto the ends of it: And there is nothing hid from the heat thereof.
7 The law of the Lord is perfect, converting the soul: The testimony of the Lord is sure, making wise the simple.
8 The statutes of the Lord are right, rejoicing the heart: The commandment of the Lord is pure, enlightening the eyes.
9 The fear of the Lord is clean, enduring for ever: The judgments of the Lord are true and righteous altogether.
10 More to be desired are they than gold, yea, than much fine gold: Sweeter also than honey and the honeycomb.
11 Moreover by them is thy servant warned: And in keeping of them there is great reward.
12 Who can understand his errors? Cleanse thou me from secret faults.
13 Keep back thy servant also from presumptuous sins; Let them not have dominion over me: Then shall I be upright, And I shall be innocent from the great transgression.
14 Let the words of my mouth, And the meditation of my heart, be acceptable in thy sight, O Lord, my strength, and my redeemer.
The Scriptures need nothing else to teach everything necessary for right belief about God and salvation. Scripture is the sufficient means by which we understand ourselves and others. Scripture is also how we see and interact with extra-biblical information in its ultimate sense. God has given us everything we need to form a God-oriented worldview and perspective (which is exclusively true) of everything we study. In other words, scripture is sufficient to enable us to see all of creation and life from a God-ordained perspective (even in the seemingly mundane affairs of life). For example...
Proverbs 6:1–5
My son, if thou be surety for thy friend, If thou hast stricken thy hand with a stranger,
2 Thou art snared with the words of thy mouth, Thou art taken with the words of thy mouth.
3 Do this now, my son, and deliver thyself, When thou art come into the hand of thy friend; Go, humble thyself, and make sure thy friend.
4 Give not sleep to thine eyes, Nor slumber to thine eyelids.
5 Deliver thyself as a roe from the hand of the hunter, And as a bird from the hand of the fowler.
Theology is not just a chapter in a systematic theology text. It specifically and powerfully impacts our lives. Listen to this quote, by a well-known preacher, as he elaborates on the knowledge of God as it applies to the benefit of man.
“It has been said by someone that “the proper study of mankind is man.” I will not oppose the idea, but I believe it is equally true that the proper study of God’s elect is God; the proper study of a Christian is the Godhead. The highest science, the loftiest speculation, the mightiest philosophy, which can ever engage the attention of a child of God, is the name, the nature, the person, the work, the doings, and the existence of the great God whom he calls his Father. There is something exceedingly improving to the mind in a contemplation of the Divinity. It is a subject so vast, that all our thoughts are lost in its immensity; so deep, that our pride is drowned in its infinity. Other subjects we can compass and grapple with; in them, we feel a kind of self-content, and go our way with the thought, “Behold I am wise.” But when we come to this master science, finding that our plumb line cannot sound its depth and that our eagle eye cannot see its height, we turn away with the thought, that vain man would be wise, but he is like a wild ass’s colt; and with the solemn exclamation, “I am but of yesterday, and know nothing.” No subject of contemplation will tend more to humble the mind, than thoughts of God. We shall be obliged to feel
‘Great God, how infinite art thou, What worthless worms are we!’
“But while the subject humbles the mind it also expands it. He who often thinks of God, will have a larger mind than the man who simply plods around this narrow globe. He may be a naturalist, boasting of his ability to dissect a beetle, anatomize a fly, or arrange insects and animals in classes with well-nigh unutterable names; he may be a geologist, able to discourse of the megatherium and the plesiosaurus, and all kinds of extinct animals; he may imagine that his science, whatever it is, ennobles and enlarges his mind. I dare say it does, but after all, the most excellent study for expanding the soul, is the science of Christ, and him crucified, and the knowledge of the Godhead in the glorious Trinity. Nothing will so enlarge the intellect, nothing so magnify the whole soul of man, as a devout, earnest, continued investigation of the great subject of the Deity. And, whilst humbling and expanding, this subject is eminently consolatory. Oh, there is, in contemplating Christ, a balm for every wound; in musing on the Father, there is a quietus for every grief; and in the influence of the Holy Ghost, there is a balsam for every sore. Would you lose your sorrows? Would you drown your cares? Then go, plunge yourself in the Godhead’s deepest sea; be lost in his immensity; and you shall come forth as from a couch of rest, refreshed and invigorated. I know nothing which can so comfort the soul; so calm the swelling billows of grief and sorrow; so speak peace to the winds of trial, as a devout musing upon the subject of the Godhead.”
Charles Spurgeon
1834-1892
Not sure I could have said it better myself! Need help?
Matthew 11:28–30
28 Come unto me, all ye that labour and are heavy laden, and I will give you rest. 29 Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls. 30 For my yoke is easy, and my burden is light.