“God has one of His names, El Shaddai, which signifies He who is sufficient or all-sufficient. God is a self-sufficient Being, and needs not anything from without Himself to support Himself, or to make Himself happy.
He is the first of beings, the first and the last; before Him there was no God formed, nor will be any after Him: from everlasting to everlasting He is God. And therefore His existence is not owing to any, nor has He received any assistance or support from any.
Being self-sufficient, He must be self-subsistent. As He existed of Himself, and subsisted in and of Himself, millions and millions of ages, even an eternity, inconceivable to us alone, before any other existed, He must be self-sufficient, and as then, so to all eternity.
He is an infinite and all-comprehending Being. To what is infinite nothing can be added. If anything was wanting in Him, He would be finite; if there was any excellency in another which is not in Him, He would not be infinite, and so not God.
But being infinite, He is incomprehensible by others, and He comprehends in Himself all excellencies, perfections, and happiness. And therefore He is self-sufficient. ‘Who hath first given to Him, and it shall be recompensed to him again? For of Fim, and through Him, and for Him, are all things,’ (Rom. 11:35-36).
God is the summum bonum, the chief good, and has all that is good in Him. He is good essentially, originally, and inderivatively. He is the source and fountain of all goodness. Every good and perfect gift comes from Him (James 1:17), and therefore He must have a fulness of goodness in Him sufficient for Himself, as well as for His creatures, and can receive nothing from them.
Otherwise, He would not be the independent Being He is: all have their dependence on Him, and all owe their being and the preservation of it to Him; but He depends on none; which He would, if He stood in need of, or received anything from them.
He is possessed of all perfections and is sufficiently happy in them. He is perfect and entire, wanting nothing, and therefore self-sufficient. He is the Fountain; creatures, and what they have, are streams. And it would be as absurd for Him to need them, or anything from them, as for the fountain to need its streams.
Besides, God in His divine persons, God, Father, Son, and Spirit, have enough within themselves, to give the utmost, yea, infinite complacency, delight, and satisfaction among themselves, and to one another, and had before any creatures were made, and would have had if none had been made, and so ever will.
The Father delighted in the Son, ‘the brightness of His glory, and the express image of His person.’ (Heb. 1:3) The Son delighted in the Father, before whom He was always rejoicing, when as yet no creature existed. And both in the blessed Spirit, proceeding from them, and He in them (Prov. 8:30), for creation adds nothing at all to the perfection and happiness of God, nor makes the least alteration in Him (Rev. 4:11).
God is an all-sufficient Being and has enough within Himself to communicate to His creatures. He is able to do whatsoever He pleases, to fulfill all His engagements and promises, and to do exceeding abundantly above all that men ask or think.
And so communicative and diffusive is His goodness, that it extends to all His creatures. And every good and perfect gift comes from Him, which is a proof of His all-sufficiency.
In His gifts of nature and providence, He gives life and breath and all things to His creatures, (Acts 17:25). A painter may paint as near to life as can be, and a sculptor may give a statue its just features, and frame its limbs in proper symmetry and proportion, but neither of them can give life and breath.
But God is sufficient to do this, and has done it: He breathed into Adam the breath of life, and gives life to all his posterity. So it is with great propriety that He is called the God of their life (Psalm 42:8).
And He is sufficient to support, maintain, and preserve the life He has given, and does, as long as He pleases, and to provide for men all the necessaries of life (Job 10:12, 12:10; Psalm 66:9).
God is all-sufficient in the communications of His grace. He is the God of all grace, and He is able to cause all grace to abound towards His people, and to supply all their wants out of that rich and glorious plenitude and all-sufficiency in Himself by Jesus Christ.
He has stored the covenant with all the blessings of grace. He has presented Christ, the head and mediator of it with all the blessings of goodness.
He has blessed His people in Christ with all spiritual blessings, and given them grace in Him before the world began. He caused the fulness of His grace to dwell in Him, which is always sufficient for them, sufficient for them in all ages and periods of time.
His grace in Christ is sufficient for them of all nations and kingdoms throughout the world, and for them in every state and condition of life, and for all believers, weak or strong.
And He has a sufficiency of it for all saving purposes: for their acceptance with God, and justification before Him; for the remission of their sins, and the cleansing of their souls, and for the supply of all their wants whilst they are in this state of imperfection.
And He has a sufficiency of it to communicate to them at all times: when they are called to service, ordinary or extraordinary, to do or suffer for His name’s sake; in times of affliction, temptation, desertion, and in the hour of death, to bear up under and carry them through all, and bring them safe to His kingdom and glory (John 1:14, 16, 2 Cor. 12:9, Phil. 4:19).”
–John Gill, A Complete Body of Doctrinal and Practical Divinity: Or A System of Evangelical Truths, Deduced from the Sacred Scriptures (vol. 1, London: Tegg & Company, 1767/1839), 1: 170–175.