Concession means a thing is granted, permitted, adjusted, compromised or modified especially in response to demands.
Moses’s bill of divorcement was a gesture made in recognition of a demand and so was Saul becoming king. The people asked Jesus, "Why did Moses then command to give a writing of divorcement, and to put her away? He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so" Matthew 19:7-8.
The people said to Samuel we want a king, "for we want to be like the nations around us...." So Samuel told the Lord what the people had said, and the Lord replied again, "Then do as they say and give them a king." So Samuel agreed..." 1 Samuel 8:19-22
Do you see why Paul said I say this as a concession, not as a commandment?
He said in chapter 6, "All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any....Now the body is not for fornication, but for the Lord; and the Lord for the body" 1 Corinthians 6:12-13.
Jesus asked some Pharisees, he said, "I will ask you one thing; Is it lawful on the sabbath days to do good, or to do evil? to save life, or to destroy it?" Luke 6:9.
Paul is saying I am making these modifications to save lives. God has called us to peace. "For what knowest thou, O wife, whether thou shalt save thy husband? or how knowest thou, O man, whether thou shalt save thy wife?" 1 Corinthians 7:16. He said, "But I speak this by permission, and not of commandment" 1 Corinthians 7:6. "...if they cannot contain, let them marry: for it is better to marry than to burn" 1 Corinthians 7:9.
But, what Paul can’t change is that commanded by God, "And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband:  Brethren, let every man, wherein he is called, therein abide with God" 1 Corinthians 7:10,24.
He said I am saying this for your benefit, not to place restrictions on you. I want you to do whatever will help you serve the Lord best, with as few distractions as possible.
You have been bought and paid for by Christ, so you belong to him set your affection on things in heaven, don’t be enslaved by the world.
Muzembi.Org - Simple Gospel Summation
|1 Corinthians||1||Called to be Saints|
|1 Corinthians||2||The wisdom of God|
|1 Corinthians||3||The Spirit of God dwells in you|
|1 Corinthians||4||Stewards of the mysteries of God|
|1 Corinthians||5||The Christian Life|
|1 Corinthians||6||Settle your own differences|
|1 Corinthians||7||Let them marry|
|1 Corinthians||8||Is there any other God?|
|1 Corinthians||9||The seal of my Apostleship|
|1 Corinthians||10||These things became our examples|
|1 Corinthians||11||Keep ordinances|
|1 Corinthians||12||Growing up in the Holy Ghost ||
|1 Corinthians||13||If I don't love, I'm nothing! ||
Pursue love and desire spiritual-gifts
|1 Corinthians||14||Spiritual gifts|
|1 Corinthians||15||What the Gospel really is!|
|1 Corinthians||16||Stand fast in the faith|