It is impossible to remain bitter towards, have a cold attitude against, or consistently mistreat some that you are effectually and fervently praying for. Effective prayer works first on the person who is doing the praying. If you are constantly bitter, angry or just plain stank with anyone … though it may be hard to hear, your slip is showing.
James 5:16 – Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much.