1 John 3:21-22:

Beloved, if our heart condemn us not, then have we confidence toward God.
And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight.

See also:

What If You Sin?
Some of God’s Promises Have Conditions
Healing and Obedience
Doesn’t 1 John 3:22 Prove That Our Ability to Receive Depends on How Well We Keep God’s Commandments?
Does UNREPENTED Sin in My Life Stop Me from Getting Healed?
Is It Possible for a New Testament Believer’s Prayer to Receive Healing to Be Hindered?
Objection: Sometimes God Says, “Yes,” Sometimes He Says, “No,” and Sometimes He Says, “Wait” When You Ask for Healing