When Abraham's fear vanished by receiving the good news of having a prophet son and grandson, (ISAAC & JACOB) and made sure that the strangers were God's Messengers who had come to punish the sinful cities of Sodom and Gomorah, he began to plead with God and dispute with the angels for the wicked people of Lot. Abraham was not sure enough that the people of Lot had already been judged, and that, God's decree had been issued. This was why he began to haggle with the angels over the sinful people, for being a Compassionate and a tender-hearted man. But when they told him plead not on this matter that God's decree has already been issued, he ceased arguing and kept quiet, sighing.