The Soul is identified in the dictionary as: The animating and vital principle in humans, credited with the faculties of thought, action, and emotion and often conceived as an immaterial entity. It is defined also as the spiritual nature of humans, regarded as immortal, separable from the body at death, and susceptible to happiness or misery in a future state. Thus in the Quran God talk to this soul which though invisible to us will separate from our body at death and will have a new body at the day of judgment. It makes a lot of sense that God talks about our souls since the body disintegrates after death. To have a new body with no soul makes no sense either since our connection from the earthy state to an eternal state is reasonably predicted to be through the original soul. Examine these verses that talk about the soul:
1- Every Soul is judged alone separate from all human souls:
2:48 Then guard yourselves against a day when one soul shall not avail another nor shall intercession be accepted for her, nor shall compensation be taken from her, nor shall anyone be helped (from outside).
وَاتَّقُواْ يَوْماً لاَّ تَجْزِي نَفْسٌ عَن نَّفْسٍ شَيْئاً وَلاَ يُقْبَلُ مِنْهَا شَفَاعَةٌ وَلاَ يُؤْخَذُ مِنْهَا عَدْلٌ وَلاَ هُمْ يُنصَرُونَ
2- The Soul earns its good deeds:
2:110 And be steadfast in prayer and regular in charity: And whatever good ye send forth for your souls before you, ye shall find it with Allah. for Allah sees Well all that ye do. وَأَقِيمُواْ الصَّلاَةَ وَآتُواْ الزَّكَاةَ وَمَا تُقَدِّمُواْ لأَنفُسِكُم مِّنْ خَيْرٍ تَجِدُوهُ عِندَ اللّهِ إِنَّ اللّهَ بِمَا تَعْمَلُونَ بَصِيرٌ
3- In the day of judgment every soul will be paid what it earns:
3:25 But how (will they fare) when we gather them together against a day about which there is no doubt, and each soul will be paid out just what it has earned, without (favor or) injustice?
فَكَيْفَ إِذَا جَمَعْنَاهُمْ لِيَوْمٍ لاَّ رَيْبَ فِيهِ وَوُفِّيَتْ كُلُّ نَفْسٍ مَّا كَسَبَتْ وَهُمْ لاَ يُظْلَمُونَ
4- It is heaven or hell:
3:185 Every soul shall have a taste of death: And only on the Day of Judgment shall you be paid your full recompense. Only he who is saved far from the Fire and admitted to the Garden will have attained the object (of Life): For the life of this world is but goods and chattels of deception.
كُلُّ نَفْسٍ ذَآئِقَةُ الْمَوْتِ وَإِنَّمَا تُوَفَّوْنَ أُجُورَكُمْ يَوْمَ الْقِيَامَةِ فَمَن زُحْزِحَ عَنِ النَّارِ وَأُدْخِلَ الْجَنَّةَ فَقَدْ فَازَ وَما الْحَيَاةُ الدُّنْيَا إِلاَّ مَتَاعُ الْغُرُورِ
5- It is the time now in earth to decide the eternal fate of your soul:
3:193 "Our Lord! we have heard the call of one calling (Us) to Faith, 'Believe ye in the Lord,' and we have believed. Our Lord! Forgive us our sins, blot out from us our iniquities, and take to Thyself our souls in the company of the righteous. رَّبَّنَا إِنَّنَا سَمِعْنَا مُنَادِيًا يُنَادِي لِلإِيمَانِ أَنْ آمِنُواْ بِرَبِّكُمْ فَآمَنَّا رَبَّنَا فَاغْفِرْ لَنَا ذُنُوبَنَا وَكَفِّرْ عَنَّا سَيِّئَاتِنَا وَتَوَفَّنَا مَعَ الأبْرَارِ
verses collected from: www.islamicity.com Translation to Yusuf Ali.