1 John 5:15

And if we can be sure that He hears our request for whatever we ask [of Him], we can [also] be certain that we [will] have whatever we have requested from Him.

Mark 11:24

Therefore I tell you, whatever things you ask for in prayer, believe that you have received them, and you will have every one of them.

Luke 11:9-10

And I tell you, ask [God for something] and it will be given to you; look [to God for something] and you will find it; knock [on the door of opportunity] and it will be opened up to you.

1 John 5:18-20

We know that every person who has been [spiritually] conceived [by God and eventually born] does not continue in [a life of] sin, but God's one and only conceived [Son] keeps him [from continuing to sin], and the evil one [i.e., Satan] does not continue to touch him [i.e., continue to control his life].

Treasury of Scripture Knowledge

Summary

And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him.

General references

Bible References

We know

Mark 11:24
Therefore I tell you, whatever things you ask for in prayer, believe that you have received them, and you will have every one of them.
Luke 11:9
And I tell you, ask [God for something] and it will be given to you; look [to God for something] and you will find it; knock [on the door of opportunity] and it will be opened up to you.

General references

Matthew 21:22
And everything you ask for in prayer you will receive, if you have [enough] faith."