1Sa 1:9-19
Then Hannah rose after eating and drinking in Shiloh. Now Eli the priest was sitting on the seat by the doorpost of the temple of the LORD. She, greatly distressed, prayed to the LORD and wept bitterly.

She made a vow and said, "O LORD of hosts, if You will indeed look on the affliction of Your maidservant and remember me, and not forget Your maidservant, but will give Your maidservant a son, then I will give him to the LORD all the days of his life, and a razor shall never come on his head."

Now it came about, as she continued praying before the LORD, that Eli was watching her mouth. As for Hannah, she was speaking in her heart, only her lips were moving, but her voice was not heard. So Eli thought she was drunk.

Then Eli said to her, "How long will you make yourself drunk? Put away your wine from you."

But Hannah replied, "No, my lord, I am a woman oppressed in spirit; I have drunk neither wine nor strong drink, but I have poured out my soul before the LORD. "Do not consider your maidservant as a worthless woman, for I have spoken until now out of my great concern and provocation."

Then Eli answered and said, "Go in peace; and may the God of Israel grant your petition that you have asked of Him."

She said, "Let your maidservant find favor in your sight." So the woman went her way and ate, and her face was no longer sad.

Then they arose early in the morning and worshiped before the LORD, and returned again to their house in Ramah. And Elkanah had relations with Hannah his wife, and the LORD remembered her.

1. Hannah asked God for a relatively mundane thing - that God would allow her to have a male child.
2. Hannah promised something in return if God honored her request.
3. God did honor her request.
4. Hannah honored her promise to God.