"Now Isaac had come from Beer Lahai Roi, for he was living in the Negev. He went out to the field one evening to meditate, and as he looked up, he saw camels approaching." NIV translation
Isaac was back at home with Abraham and we see that he went out to meditate. The Hebrew word for meditate is hagah and it is not the quiet reflection that we think of. Isaac had lost his mother and now he could surely see that the time of his father was close. He was going to be without any family and was probably crying out to God. Then, he looks up and sees the woman that God has created to be his wife. It is awesome to know that, when we cry out to God (meditate), He listens and will show us His provision!
"Rebekah also looked up and saw Isaac. She got down from her camel and asked the servant, 'Who is that man in the field coming to meet us?' 'He is my master,' the servant answered. So she took her veil and covered herself." NIV translation
At the same time, Rebekah saw Isaac and asked who he was. What a wonderful picture of God's perfect timing as they saw each other at the same time. She, then covered herself with her veil which must have been a sign that she was unmarried.
"Then the servant told Isaac all he had done. Isaac brought her into the tent of his mother Sarah, and he married Rebekah. So she became his wife, and he loved her; and Isaac was comforted after his mother's death." NIV translation
We see that they did not have a ceremony or even a marriage license or certificate. They were simply together physically and were considered to be married. As we shall see the result of this arranged marriage will be a chosen people for the Lord.