Hebrews 4:16:

Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need.

See also:

Who You Are and What You Have
Set Free from Fear of Punishment
Jesus Opened Heaven
Free Access to the Throne!
The Insecure Preacher
What 1 John 1:9 Really Means
What Happened Between the Cross and the Throne
Objection: God Uses Sickness to Draw Us Closer to Himself
Objection: Jesus Literally Said to “Keep On Asking.”  Therefore, We Should Bug God Like the Widow in Jesus’ Parable
Objection: It Is Humbler to Ask for Grace Than to “Claim Your Rights”