The body has its senses, and the spirit also has its senses. The spirit dwells in the body and has a very close relationship with the body; nevertheless, it is completely different from the body. The body has various senses, but a spiritual man can detect that which is beyond his physical senses. There is another sense in the innermost part of his being which can rejoice, grieve, fear, approve, condemn, determine, and discern. These are the senses of the spirit which are distinct from the senses of the soul expressed through the body.
The senses and functions of the spirit can be seen from the following verses:
"The spirit is willing" (Matt. 26:41).
"Jesus, knowing fully in His spirit" (Mark 2:8).
"He groaned deeply in His spirit" (Mark 8:12).
"My spirit has exulted in God my Savior" (Luke 1:47).
"The true worshippers will worship the Father in spirit and truthfulness" (John 4:23).
"He...was moved with indignation in His spirit" (John 11:33).
"When Jesus had said these things, He became troubled in His spirit" (John 13:21).
"His spirit was provoked within him as he beheld that the city was full of idols" (Acts 17:16).
"This man was instructed in the way of the Lord, and being fervent in spirit" (Acts 18:25).
"Paul purposed in his spirit" (Acts 19:21).
"I am going bound in the spirit to Jerusalem" (Acts 20:22).
"Burning in spirit" (Rom. 12:11).
"For who among men knows the things of man, except the spirit of man which is in him?" (1 Cor. 2:11).
"I will sing with the spirit" (1 Cor. 14:15).
"If you bless with the spirit" (1 Cor. 14:16).
"I had no rest in my spirit" (2 Cor. 2:13).
"Having the same spirit of faith" (2 Cor. 4:13).
"A spirit of wisdom and revelation" (Eph. 1:17).
"Your love in the Spirit" (Col. 1:8).
Now we can see how keen the sense of man’s spirit is and how numerous its functions are. The Bible does not say man’s heart senses and functions in this way, but his spirit does sense or function in this way. We must read the above verses very carefully to realize that the human spirit possesses all these functions. After thoroughly reading them, we will see that the functions and senses of the human spirit are as inclusive as those of the soul. Whether it is thoughts, decisions, or feelings, as long as it is something that the soul has, the spirit has it also. This shows us how important it is to learn to distinguish the spiritual from the soulish. As a believer passes through the deep work of the cross and Holy Spirit, he gradually becomes experienced and knows what is of the soul and what is of the spirit.
(Spiritual Man, The (3 volume set), Chapter 19, by Watchman Nee)