At heart God is love. But love cannot exist in isolation, it yearns for others outside of itself whom it can love and make happy.  This need of God to love those other than himself is expressed many times in the Bible: –

Then God said, “Let us make man in our image, after our likeness”.
[Genesis 1:26  ESV]

Having loved his own who were in the world, he loved them to the end.
[John 13:1 ESV]

God abides in us and his love is perfected in us.
[1 John 4:12 ESV]

But whilst love for others may be the motivating power behind the created universe and the human race, it cannot entirely account for it. A God who was love alone might have a heartfelt longing for creation but that longing could never be more than an unfulfilled dream without the means to achieve it.

Alongside his love God also has know-how, a wise knowledge and understanding of how creation might be constructed and work.  Every created form, from our whole solar system to each individual atom in it, speaks of intelligence, knowledge, and design. The psalmist in his observation of creation perceives the voice of wisdom speaking through it: Day to day pours out speech, and night to night reveals knowledge  [Psalm 19:2  ESV]. Like a craftsman who loves to create pleasing forms, God also has knowledge of his materials, skill in using his tools, and wisdom in putting together the finished article. Such wisdom perfectly complements God’s love and neither of them is anything without the other.

Yet even a twofold God, in whom such love and wisdom were combined, would be impotent without a vital third element. In and through his creation, God is active and useful. His constant endeavour is one of service and he is always busy working to care for others and bless them with happiness. This useful endeavour brings to full fruition all that his love desires and his wisdom plans. These three essentials combine together to make the one God. They are the trinity without which God would be nothing more than an empty notion, and the created universe with all its life forms could not exist. Emanuel Swedenborg speaks often of this trinity of essentials in God as, for example, in the following summary:

There are three elements in the Lord which are the Lord, the Divine element of love, the Divine element of wisdom, and the Divine element of useful endeavour.
[Divine Love and Wisdom 296]

When writing of these essentials in the Lord God, Swedenborg occasionally speaks of them being “distinctly one”.  By this he means that whilst each essential – love, wisdom and use – can be known and understood as a distinct thing, each is such an integral part of the others that they only have reality and existence as a unity. In every moment, in God’s work of creation, preservation and salvation of the human race, all three essentials are distinctly one. They can no more have separate existence than could the heat, light and proceeding energy which together constitute our sun; or the vegetable matter, beautiful form and scent which together are a garden flower.

Every time God touches our lives, his love, wisdom, and useful endeavour are each working in perfect balance and harmony.  In these three essentials we have an insight into the Holy Trinity which has been at the heart of God since the very beginning.  The trinity is not three separate gods or even three separate persons, but is rather one God activating all the elements within himself in every work that he undertakes.  It was in recognition of this trinity within one God that the seraphim spoke their words of praise, Holy, holy, holy is the Lord of hosts; the whole earth is full of his glory [Isaiah 6:3  ESV]. The threefold repetition of the word, ‘holy’, speaks of the three essentials, but the singular word, ‘Lord’, speaks of one Divine Person in whom those essentials exist.

Emanuel Swedenborg gives us further insight into the necessity for a trinity of essentials in God when he writes, In every Divine work there is a first, a middle, and a last; and the first passes through the middle to the last, and thereby exists and subsists [Doctrine of Sacred Scripture 27].  Love must work through wisdom to accomplish any useful endeavour.  It seems that a trinity of essentials is required if there is to be completeness in any person or thing, as is confirmed by this further passage, By three, in the Word, in the spiritual sense, is meant what is complete and perfect; also the whole together [Doctrine of Sacred Scripture 29]. A God in whom there are three essentials is a complete God both in himself and in everything that he does.

Finally, it is also worth reflecting that, as human beings, we are made in the image and likeness of God (see Genesis 1:26 above). Because we draw our life from God it is hardly surprising that in each of us there is also a trinity of three essentials, for we too are capable of love, wisdom and useful endeavour. Each of these three essentials has to be active in every loving relationship we have with others and in every useful task that we properly discharge. It is only as we receive the fullness of God’s life in its threefold form that we can be complete in all that we strive to be and do.

http://www.god-is-love.org.uk/