Today's Scripture reading is Hebrews 4:1-3.
Verse 1, "Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it."
When we came to the Lord Jesus, we came as sinners headed for an eternity in Hell.  Whether we were in the children-teen years or already an adult, our sin was going to take us to the same eternal home.  The Lord Jesus changed our everything and especially our final dwelling place.  There is no question in my mind that I fell way short of it.  This is confirmed in Romans 3:23, "For all have sinned and come short of the glory of God."  We are encouraged in Hebrews 4:1 to rest in the finished work of the Lord Jesus.  When I accepted Him by faith as my personal Saviour, I entered into His rest.  It is not necessary for me lose any sleep wondering if I am saved.  His death, burial and resurrection paid the eternal price for me to rest now and for all eternity.