Let...

"Do not let your hearts be troubled (distressed, agitated) you believe in God; believe also in Me...Peace I leave with you; My [own] peace I now give and bequeath to you. Not as the world gives do I give to you, Do not let your hearts be troubled; neither let them be afraid." (John 14: 1, 26-27)

Editorial: "Let" is an action verb ~ You decide what you "let" happen, so do not LET your heart be troubled...

Instead, LET your heart, mind, etc... think on these things...

"...whatever is true, whatever is honorable, whatever is right, whatever is pure, whatever is lovely, whatever is of good repute, if excellence and if anything worthy of praise, dwell on these things...practice these things, and the God of peace will be with you." (Phillipians 4:8)