The soul corresponds to the ego with a nuance of interiority and living power as in "As truly as my soul lives!" (Dt 32:40, Am 6:8, 2 Co 1:23)
"Love the Lord your God and serve Him with all your heart and all your soul."
(Deut 11.13, Jos 22.5, 1 Kgs 2.4, Mark 12.33)
Therefore it may be possible to love and serve God with your heart but not your soul. Your soul's love and service is all important.
"When he had finished speaking to Saul, the soul of Jonathan was knit to the soul of David, and Jonathan loved him more than his own soul. Then Jonathan made a covenant with David, because he loved him as his own soul.""
(1 Sam 18.1, 3)
Souls can indeed mate and soulmates are compelled to form covenanted relationships, Jonathan's foreshadowing the Lord's and the Holy One's (Jesus').
"Incline your ear, and come to Me; hear, that your soul may live; and I will make with you an everlasting covenant, my steadfast, sure love for David." (Isa. 55:3)"To the eunuchs who keep my sabbaths, who choose the things that please me and hold fast my covenant, I will give in my house and within my walls a monument and a name better than sons and daughters." (Isa 56:5)
This covenant does not depend upon gender roles -- men, women, eunuches are all able to covenant soul-to-soul.
"He whose soul is not upright in him shall fail." (Hab 2:4)