'Lookout' in the Bible

in the day when the keepers of the house (hands, arms) tremble, and the strong men (feet, knees) bow themselves, and the grinders (molar teeth) cease because they are few, and those (eyes) who look through the windows grow dim;

Jesus repeatedly ordered them, saying, “Watch out! Beware of the leaven of the Pharisees and the leaven of Herod.”

Look out for the dogs [the Judaizers, the legalists], look out for the troublemakers, look out for the false circumcision [those who claim circumcision is necessary for salvation];