Now similar difference is there between a Soul & Supersoul (God). Soul is limited while Supersoul is infinite. Soul can get contaminated with the qualities of nature (Sattva, Rajas & Tamas) but Supersoul is beyond the qualities of nature but the Lord of the nature. Soul is a spark of the Supersoul & just like many sparks coming out of fire, all these different souls have come from the Supersoul only. Below verse of "Mundaka Upanisad" explains that only:
"tat etat satyam yatha su-diptat pavakad
visphulingah sahasrasah prabhavante
sa-rupah tathaksharad vividhah saumya
bhavah prajayante tatra caivapi yanti"
The Supreme God is real and eternal. As many thousands of sparks come from a blazing fire, so many different living entities are manifested from the imperishable Supreme God and then again go & merge into Him.
Now how this little Soul is different from the Supersoul (God) in nature. Though soul is part & parcel of Supersoul (God) only & both are unborn, imperishable but still one is limited in capacity & power while other is Lord of unlimited power. Actually soul is the enjoyer of fruits of this vast nature, while Supersoul (God) is the provider of all these fruits & simply watches the actions & play of these different souls.
Mundaka Upanisad compares the soul and the Supersoul as two friendly birds sitting on the same tree (the tree of nature). One of the birds (the individual soul) is eating the fruit of the tree, while the other bird (Lord Krishna or God) is simply watching his friend. Of these two birds, although the same in quality, one is captivated by the fruit of the material tree (this material world) while the other is keeping watch only. Although they are friends, one is the master and the other is the servant. Forgetfulness of this relationship by the individual soul is the cause of one's changing his position from one tree to another, or similarly from one body to another. The Jiva, or individual soul, is struggling very hard on the tree of the material body, but as soon as it agrees to accept the other bird as the Supreme spiritual master, as Arjuna agrees to do by voluntary surrender unto Krishna for instruction, the subordinate bird immediately becomes free from all lamentations.
"dva suparna sayuja sakhaya
samanam vriksham praishasvajate
tayor anyah pippalam svadv
atty anasnann anyo 'bhicakasiti"
In the individual spirit soul and the Supersoul, Supreme Personality of Godhead, are like two friendly birds sitting on the same tree. One of the birds (the individual atomic soul) is eating the fruit of the tree (the sense gratification afforded by the material body), and the other bird (the Supersoul) is not trying to eat these fruits, but is simply watching His friend.
"samane vrikshe purusho nimagno
'nisaya socati muhyamanah jushtam
yada pasyati anyam isam asya
mahimanam iti vita-sokah"
Although the two birds are on the same tree, the eating bird is fully engrossed with anxiety and moroseness as the enjoyer of the fruits of the tree. But if in some way or other he turns his face to his friend who is the Lord, and knows His glories, at once the suffering bird becomes free of all anxieties.
Below are also verses from Bhagwat Gita which too explain about the nature of soul & Supersoul:
"dvav imau purushau loke
ksharas chakshara eva cha
ksharah sarvani bhutani
kuta-stho ’kshara ucyate" (Bhagwat Gita: Chapter Fifteen verse 16)
"Sri Krishna said: O Arjuna, There are two classes of beings, the fallible and the infallible. In the material world every living entity is fallible, and in the spiritual world every living entity is called infallible."
"uttamah purushas tv anyah
yo loka-trayam avisya
bibharty avyaya ishvarah" (Bhagwat Gita: Chapter Fifteen verse 17)
"Sri Krishna said: O Arjuna, Besides these two, there is the greatest living personality, the God Supersoul, the imperishable Lord Himself, who has entered the three worlds and is maintaining them."
"yasmat ksharam atito ’ham
aksharad api cottamah
ato ’smi loke vede cha
prathitah purushottamah" (Bhagwat Gita: Chapter Fifteen verse 18)
"Sri Krishna said: O Arjuna, Because I am transcendental, beyond both the fallible and the infallible, and because I am the greatest, I am celebrated both in the world and in the Vedas as that God Supersoul Person."