"He Who has created all things in the best possible way. He commenced the creation of man from clay; then produced his seed from an extract of base fluid; then formed him and breathed His Soul into him and gave you hearing, sight and hearts. What little thanks you show!" (Surat as-Sajda, 7-9) Allah breathed of His own spirit, giving eyes and hearts to human beings whom He created with a sublime creation and to whom He gave reason and consciousness. The soul belongs to Allah; the soul that people refer to as theirs is actually the spirit of Allah. With His omniscience and infinite creative power, Allah performs this creation in such a perfect manner that, as a part of the test, people are able to assume ownership of this soul bestowed on them and say it is "mine." - Harun Yahya
So the Human soul is our link with God. When we are in perfect communion with our soul, weve fulfilled existence in God. In Vedic thought, this state is known as sat-chit-ananda (existence, consciousness, bliss) or samadhi.
And it came to pass that Ilúvatar called together all the Ainur and declared to them a mighty theme, unfolding to them things greater and more wonderful than he had yet revealed; and the glory of its beginning and the splendour of its end amazed the Ainur, so that they bowed before Ilúvatar and were silent. Then Ilúvatar said to them: 'Of the theme that I have declared to you, I will now that ye make in harmony together a Great Music. And since I have kindled you with the Flame Imperishable, ye shall show forth your powers in adorning this theme, each with his own thoughts and devices, if he will. But I win sit and hearken, and be glad that through you great beauty has been wakened into song.' - JRR Tolkien, Ainulindale, The Silmarillion