"A certain man of Zorah, named Manoah, from the clan of Danites, had a wife who was sterile and remained childless. The angel of the LORD appeared to her and said, 'You are sterile and childless, but you are going to conceive and have a son. Now see to it that you drink no wine or other fermented drink and that you do not eat anything unclean, because you will conceive and give birth to a son. No razor may be used on his head, because the boy is to be a Nazirite, set apart to God from birth, and he will begin the deliverance of Israel from the hands of the Philistines.' The woman went to her husband and told him... Then Manoah prayed to the LORD: 'O Lord, I beg you, let the man of God you sent to us come again to teach us how to bring up the boy who is to be born.' God heard Manoah, and the angel of God came again to the woman while she was about in the field... So Manoah asked him, 'When your words are fulfilled, what is to be the rule for the boy's life and work?' The angel of the LORD answered, 'Your wife must do all that I have told her. She must not eat anything that comes from the grapevine, nor drink any wine or other fermented drink nor eat anything unclean. She must do everything I have commanded her.' The woman gave birth to a boy and named him Sampson. He grew and the Lord blessed him, and the Spirit of the LORD began to stir him while he was in Maheneh Dan, between Zorah and Eshtaol."
Judges 13:17-23 is also incredible! Manoah and his wife came face to face with God, having one of the most incredible encounters with God recorded in the OT, something that would not have happened if they had been able to conceive children. It just proves that the blessing in infertility is a deeper knowledge, understanding, and appreciation of our Sovereign, Almighty God!!