Note 1 at Mt 9:38: People are born again through the power of the Word of God (Ro 10:14-17 and 1Pe 1:23), not through prayer. Prayer is very important, but it is not a substitute for the Gospel (Ro 1:16-17). Many of us petition God for others to be saved and can't understand why it hasn't happened yet. We don't have to ask the Lord to save people. He isn't willing that anyone should perish (2Pe 3:9). He has already made provision for everyone's salvation (Joh 3:16 and 1Jo 2:2).

So, what do we pray concerning others coming to the Lord? Jesus said to pray that the Lord would send laborers across their paths (this verse). They need to hear the Word (Ro 10:14-17). Also, we should bind the influence of the god of this world (Satan) who tries to blind them to spiritual truth (2Co 4:4).

God is more motivated to save our loved ones than we are. We don't need to plead with Him, but rather we need to become a channel for Him to flow through to reach those people. We do that by sharing the good news (Gospel) with them and/or praying that other Christians will come across their paths who will do the same.