What does the Bible say about not letting our hearts be troubled?

In John 14:1, Jesus instructs his disciples, 'Let not your heart be troubled: ye believe in God, believe also in me.' This command reassures believers that despite the trials and sins they may face, their faith in Christ provides a foundation for peace. The context reveals that this declaration comes after Jesus foretells Peter's denial and acknowledges the difficulty the disciples will encounter. However, the assurance is clear: through faith in Christ, who is Savior and Lord, believers can find solace amidst struggles and uncertainties, knowing that their salvation and hope do not depend on their own righteousness but on His steadfast grace.