Genesis 25:19 These are the generations of Isaac, Abraham’s son: Abraham fathered Isaac, and Isaac was forty years old when he took Rebekah, the daughter of Bethuel the Aramean of Paddan-aram, the sister of Laban the Aramean, to be his wife. And Isaac prayed to the LORD for his wife, because she was barren. And the LORD granted his prayer, and Rebekah his wife conceived.
1 Samuel 1:11 And she vowed a vow and said, “O LORD of hosts, if you will indeed look on the affliction of your servant and remember me and not forget your servant, but will give to your servant a son, then I will give him to the LORD all the days of his life, and no razor shall touch his head.”
1 Samuel 1:27 For this child I prayed, and the LORD has granted me my petition that I made to him.
Psalms 50:15 and call upon me in the day of trouble; I will deliver you, and you shall glorify me.”
Psalms 65:2 O you who hear prayer, to you shall all flesh come.
Psalms 91:15 When he calls to me, I will answer him; I will be with him in trouble; I will rescue him and honor him.
Isaiah 45:11 Thus says the LORD, the Holy One of Israel, and the one who formed him: “Ask me of things to come; will you command me concerning my children and the work of my hands?
Isaiah 65:24 Before they call I will answer; while they are yet speaking I will hear.
Isaiah 58:9 Then you shall call, and the LORD will answer; you shall cry, and he will say, ‘Here I am.’
Luke 1:13 But the angel said to him, “Do not be afraid, Zechariah, for your prayer has been heard, and your wife Elizabeth will bear you a son, and you shall call his name John.
Isaac prayed and even the son of promise did not come into the promise easily. It only came through waiting and prayer. We can trust that the prayers of a husband for his wife have a special effectiveness. This prayer was answered, but some 20 years after Isaac and Rebekah first married. Their faith and persistence in prayer was tested and invited to grow through many years. As well, these were the only children born to Isaac and Rebekah. (Guzik)
Though God had promised to multiply his family, he prayed for it; for God’s promises must not supersede, but encourage our prayers, and be improved as the ground of our faith. Though he had prayed for this mercy many years, and it was not granted, yet he did not leave off praying for it. (Benson)
Isaac seems not to have been much tried, but to have spent his days in quietness. Jacob and Esau were prayed for; their parents, after being long childless, obtained them by prayer. The fulfilment of God’s promise is always sure, yet it is often slow. The faith of believers is tried, their patience exercised, and mercies long waited for are more welcome when they come. Isaac and Rebekah kept in view the promise of all nations being blessed in their posterity, therefore were not only desirous of children, but anxious concerning every thing which seemed to mark their future character. In all our doubts we should inquire of the Lord by prayer. (Henry)
Isaac’s marriage, like Abraham’s, was for a long time unfruitful; not to extreme old age, however, but only for 20 years. The seed of the promise was to be prayed for from the Lord, that it might not be regarded merely as a fruit of nature, but be received and recognised as a gift of grace. At the same time Isaac was to be exercised in the patience of faith in the promise of God. After this lengthened test, Jehovah heard his prayer in relation to his wife. (Keil and Delitzsch Biblical)
It is important to recognize that our prayers are heard by God and answered howbeit in His timing, not ours, in His purpose and will not ours. Abraham faithfully waited 25 years believing in God. Isaac waited 20 years believing in God. Do not let God’s timing of His answer to your prayers weaken your faith in Him and His ability to answer. He hears your prayer before the words leave your lips. Grow in patient-reliant faith and do not allow Satan to have any ground towards unbelief. God can do more than we ask and much more than we can imagine.