Our “rational soul” or “mind” has a “potential existence before its appearance in human life”

In the human, worldly soul signifies the "rational being, or mind." This has a potential existence before its appearance in human life. It is like unto the existence of a tree within the seed. The existence of the tree within the seed is potential: but when the seed is sown and watered, the signs thereof, its roots and branches, and all of its different qualities, appear. Likewise, the "rational soul" has a potential existence before its appearance in the human body, and through the mixture of elements and a wonderful combination, according to the natural order, law, conception, and birth, it appears with its identity.

What happens to one's spirit after it leaves the body

Thou has asked concerning the spirit and its immortality after its departure. Know thou that at the time of its translation it ascends and ascends until it reaches the presence of God, clothed in a temple (body) which will not become subject to the changes wrought by ages and cycles, nor by the contingencies of the world, nor the emanations thereof.
It will continue to exist through the eternity of the Kingdom of God -- its sovereignty, its dominion, its potency. From it will appear the signs of God and his qualities, the providence of God and his bestowal. Verily the pen is unable to move in a befitting manner in explaining this truth -- its exaltation and loftiness.

Question: "How can one love another whose personality is unpleasant?”

Answer: ''We are creatures of the same God. We must therefore love all as children of God even though they are doing us harm. Christ loved his persecutors. It is possible for us to attain to that love. God manifested his love by creating man in His own image. Man must manifest his love by developing himself and others more and more in the image of God. The true fruit of man is, therefore, love. The purpose of a tree is to produce fruit. Man is like a tree; his fruit should be love." (‘Abdul-Baha, Unity Through Love; p. 27; Star of the West, vol. 8, no. 10, Sept. 1917)

We each have two types of susceptibilities – physical and spiritual in character

Man is possessed of two types of susceptibilities. One is physical, the other spiritual, in character.

Physical susceptibilities have certain avenues of expression, and spiritual susceptibilities likewise have their avenues. The physical or material susceptibilities have their channels of expression in the physical realm. Earthly fraternity is due either to a family relationship, or to a commercial bond, or to a bond of love based upon policy or politics, or to a racial bond which supplies that affection, or to a bond patriotic in foundation. These are physical susceptibilities and ordinary outward love.

But spiritual susceptibilities, namely, real love and heavenly fraternity, emanate through divine channels. They emanate from faith, or they emanate from knowledge, or they emanate from the bounty of the Holy Spirit or they emanate from the effulgence of the Sun of Reality.