This is an exert from "How To Bring Men To Christ" by R. A. Torrey:
But how is one to get a love for souls? This question is easily answered. First of all a love for souls like very other grace of Chris- tian character is the work of the Holy Spirit. If then we are conscious that we do not have that love for souls that we should have, the first thing to do is to go to God and humbly confess this lack in our lives and ask Him by His Hol y Spirit to supply that which we so sorely need and expect Him to do it (i. Jno. V. 14, I5i Phil. iv. 19). In the second place Jesus Christ had an intense love tor souls (Matt, xsiii. 37; Luke xix. 10), and intimate and constant companionship with Him will impart to our lives this grace hich was so prominent in His. In the third place feelings are the outcome of thoughts. If we desire any given feeling in our lives we should dwell upon the thoughts which are adapted to produce that feeling. If any saved person will dwell upon the peril and wretchedness of any man out of Christ and the worth of his soul in God's sight as seen in the death of God's Son to save him, a feeling of intense desire for that man's salvation is almost certain to follow. In the fourth place, reflection upon our own ruined and unhappy condition without Christ and the great sacrifice that Christ made to save us, is sure to fill our hearts with a desire to bring others to the Saviour that we have found.