Poor Jordan was hoodwink by the rest of the Arab countries . It had a small but highly efficient military,  the famous The Jordanian Legion trained by the British that the Arab countries wanted to attack  Israel which it did with much reluctance.  The Arab command  then took control of the Legion but used it for their own purposes  that didn't include defending Jerusalem ,  which  Jordan  regarded as their sacred duty defend and allow to be open to all religions.  As a result to the ever lasting shame  Jordan lost the city they had controlled  and nurtured for hundreds of years.   Jordan has never forgiven the other Arab states.