Explain Mr.Linder's proposal to the Younger family. Why is he making this proposal??

Mr. Lindner tells Beneatha and Walter that the Clybourne Park Improvement Association is willing to pay them more than their down payment if they will abandon their plans to move into the neighborhood. Beneatha, having suspected his intentions, is the first to react with sarcasm. Walter, taken aback, gathers his thoughts and tells the visitor to get out. Mr. Lindner, placing his business card on the table, leaves. Lindner is trying to stop a black family from moving into the white neighborhood.