"Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ. Through him we have also obtained access by faith into this grace in which we stand, and we rejoice in hope of the glory of God." - Romans 5:1-2 ESV
This is such a loaded passage.
We have access to the grace we are standing in through (and because of) Jesus Christ.
Because of the fall people get disconnected from things they are standing in all the time. They lack access. They stand in a place but miss the beauty of their surroundings. They stand in a family but they are cut off from the warmth and connection of what a family is (or should be). They stand in marriages but lack intimacy.
We gain access to grace through Jesus Christ. We gain access to the knowledge that God is thinking kind thoughts about us. We are connected to the fact that we have favor with God based on the work and character of His Son. This access causes us to rejoice and have hope that God's 'glory' will be manifested in the world.
I see people get disconnected all the time. If the isolation happens and is sustained for long periods of time people start to get strange in their thinking. It is like they have spiritual oxygen deprivation.
Jesus is our access to intimacy. He is the master key that opens all doors. He is how we can have access to what is real and not imagined. Faith in Him can heal our other connections. Peace and justification come into our lives and we get restored over time.
"For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband..." - 1 Corinthians 7:14a ESV
Yes. Holiness can enter the home, workplace or nation because of one believing person who has access to what they are standing in.