I don't know if I can give a more clear scripture than the one I gave you in Proverbs.
But the Bible is full of examples of how we can affect God. Much of this is done through prayer. We can do things that cause God to respond. Jesus said in John 14:13 "Whatever you ask in my name, I will do."
Paul gave this advice in Phillipians 4:6,7 - "Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus." We ask, he responds.
But isn't God unchangeable? Of course. But he can still be affected by us. Look at Jonah 3:10 - "When God saw what they did and how they turned from their evil ways, He had compassion and did not bring the destruction He had threatened." Genesis 6:6,7 it says, "The LORD was grieved that he had made man on the earth, and his heart was filled with pain. So the LORD said, "I will wipe mankind, whom I have created, from the face of the earth - men and animals, and creatures that move along the ground, and birds of the air - for I am grieved that I have made them." Did God do this? No, He changed His mind and saved Noah, his family, and the animals.
But where does it say that a MANS PRAYER can change Gods mind? Look at Exodus 32:10 - "Now leave me alone so that my anger may burn against them and that I may destroy them. Then I will make YOU (Moses) into a great nation." But Moses pleaded for the people and finally God said in vs 14: "Then the LORD relented and did not bring on his people the disaster he had threatened. "
My point in all of this is that WE CAN AFFECT GOD! He is not a distant entity that couldn't care less about us. We can cause him to feel pain and sadness and to grieve in his heart. Conversely we can make him rejoice in us and make his heart happy.
Jesus himself said that the Angels even rejoice when we are saved at Luke 15:10. In fact it says that is joy within the presence of angels. That would include God too.