Hebrews 4:14-16
14Therefore, since we have a great high priest who has gone through the heavens, Jesus the Son of God, let us hold firmly to the faith we profess. 15For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are—yet was without sin. 16Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.
Our high priest, the person who mediates between us and God, is Jesus. We don't need anyone to go before God for us, because he is there on our behalf. The great news is that this high priest, Jesus, experienced all the suffering and temptation we experience. Whatever situation we are in, he knows what it is like. He experienced pain, rejection, joy, sorrow, friendship, betrayal and whatever you're going through now. He knows what it is like.
And because He experienced every temptation we face but did not sin, then took our sin on himself on the cross, we can approach Him with confidence, not a confidence based on anything we've done but on what He's done. Confidence that, despite everything we've done, He shows us mercy and grace.