I believe if we don't forgive it will not affect our eternal salvation but will affect our current earthly life negatively
Then you have not read the Bible, it is written, the measure you give is the measure you get. Mathew 18 21-35.
“Not seven times, but seventy-seven times.
The kingdom of heaven is like the king who wanted to settle accounts with his servants. As he began the settlement, a man who owed him ten thousand bags of gold was brought to him. Since he was not able to pay, the master ordered that he and his wife and his children and all that he had be sold to repay the debt. At this, the servant fell on his knees before him. “Be patient with me,” he begged, “and I will pay back everything.”
The servant’s master took pity on him, cancelled his debt, and let him go.
But when the servant went out, he found one of his fellow servants who owed him a hundred silver coins. He grabbed him and began to choke him. “Pay back what you owe me!” he demanded. His fellow servant fell to his knees and begged him, “Be patient with me and I will pay it back,” but he refused to wait for the man to repay him. Instead, he had the man thrown into prison until he could pay back the debt.
When the other servants saw what had happened, they were outraged and went and told their master everything that had happened. The master called the servant back in. “You wicked servant,” he said, “I cancelled all your debt because you begged me to. Shouldn’t you have had mercy on your fellow servant, just as I had on you?”
In anger, his master handed him to the jailer to be tortured until he could pay back all that he owed.
This is how my heavenly Father will treat each of you unless you forgive your brother or sister from your heart.”