1 John 5:14-15:

And this is the confidence that we have in him, that, if we ask any thing according to his will, he heareth us:
And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him.

Notes on 1 John 5:14-15:

How can you KNOW that what you’re requesting is God’s will?  The foremost way to know is to know His Word on the matter!  (You have to read His Word to know what is in it.)  There are cases where you may have a direct word from Him about something.  In such a case, that direct word will never contradict God’s written Word.  In a case where God has already given you His Word in the Bible, you do not need any further word from Him.  For example, you don’t need a direct word that He wants to heal you of a particular disease.  You have His Word that His will is to heal you of ALL diseases!  It’s a mistake to wait for a specific word when you have a general word.  For another example, you don’t have to ask for a specific word that it’s okay to share Jesus with someone.  He already told you as part of His Church to go into all the world and tell everyone the gospel.

We don’t know that He hears us AFTER we get what we ask for.  We have confidence that He hears us and will do what we ask when we know UP FRONT what His will is.

See also:

Pre-approved for Healing
Mistaken Prayer Mindsets
No Limits
We Hold the Keys
Objection: We Had 24/7 Prayer Asking God to Heal So-and-So, and He Chose Not to Do It
Objection: Before We Pray for a Healing in Faith, We Must Pray to See If It Is God’s Will in This Case
Objection: My Trials Only Come to Make Me Strong
Objection: Jesus Literally Said to “Keep On Asking.”  Therefore, We Should Bug God Like the Widow in Jesus’ Parable.