Ask, and it shall be given to you
Matthew 7:7–8 (ASV 1901)
7Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you: 8for every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.
Latching onto the promise in Mathew 18:19, George Müller and the ill-treated wife of an unbelieving man petitioned God repeatedly for his salvation. Eventually, God answered them, making a convert out of this former persecutor.
George Müller shares an amazing story on the power of persevering in prayer, even if it be for many years; once convinced that the subject of prayer is in line with God's will.
After years of delay, George Müller's persistent and expectant prayers for the salvation of five individuals starts to get answered. Two of the five who had yet to come to Christ when he died, eventually did - making the answers to his prayers complete.
George Müller had a particular prayer request he brought before God every day that was still unanswered. Yet, twenty-nine years after he first brought this request to God, Mr. Müller writes about his unwavering faith and belief that God will eventually answer his prayer.
Zhang Rongliang's Bible - a serious contraband and other documents are discovered in prison. He prays to God, asking that: "this storm be immediately calmed", and in the most unbelievable way, he recovers everything that was taken.
Nabeel Qureshi clings strongly to Mathew 7:7-8 as he sought clarity from God about the genuineness of Islam and Christianity. It took five months, but God answered him.
Esther Chang admonished a family of young believers to ask of the Lord whenever in need and He will answer. They take heed and a month later, God uses her to answer their prayers for food.