Today my four year old asked me why someone we knew was sick. To my knowledge she did not know that person was sick so I took it as a sign and told her "I don't know, let's pray for them" and we did. If someone crosses your mind don't take it lightly, pray for them. It doesn't have to be a long prayer but take the time to cover them in the Blood of Jesus and lift them up in prayer.
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.