From “New Spirit Filled Life” Bible, NKJV: 1 John 5:14-15—
“Now this is the confidence that we have in Him, that if we ask anything according to His Will, He hears us. And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him. ” Footnote on the above Scripture: “Children of God may have confidence of free access and boldness of speech in presenting their requests to Him. There is, however, a limitation to the assurance that our prayers will be answered. The New Testament elsewhere bases the assurance on asking in JESUS’ name (John 14:14 and 16:23-24), abiding in Christ and allowing His Words to abide in us having faith and being righteous in life and fervent in prayer. “Here John says that we must ask ACCORDING TO HIS WILL, which inclusively states the fundamental condition for assurance in prayer. One who abides in Christ and whose words abide in him; who prays in the name of Jesus, that is, in accord with His character and nature; and who is full of faith and righteousness is not inclined to pray anything contrary to His Will. But more than how we pray, God Wills and cares that we pray. “Genuine prayer is not an attempt at precise means of getting God to meet our desires and demands; but rather, in subordinating our Will to His, we open the doorway to His fullest blessings being released in our lives.”
(Refer to August 1, 1999 about S.T.P., Surrender, Trust, and Praise).
Here John…states the fundamenal condition for assurance in prayer.