There are hundreds, perhaps thousands of books about establishing boundaries in relationships.
From reading almost any of these books you will see that healthy boundaries in every relationship come from a deep sense of true love. God has established boundaries or conditions for his children. Likewise people establish boundaries with one another to make their bonds stronger and keep their relationships healthy.
The first condition of Christianity is found in John 3:16 – whosoever believeth – believe. Additionally he created ten commonly known rules for his children to follow – encouraging his children to behave and get along with each other. These are the Ten Commandments found in Exodus 20 or Deuteronomy 5.
While unconditional love is a whimsical fantasy, love with conditions or boundaries is lasting. It hopes for reciprocity. It produces a stronger, safer bond once there is reciprocity.
If you have any doubts, pick up your Holy Bible and know God’s boundaries. If you are not familiar with the importance of boundaries in personal relationships, whether with spouse, family, or friends pick up one or more of the self help establishing boundaries books that can be found on any search engine.