John the Baptist was sure of baptizing the Lord. He saw the Dove and the Sound saying, "This is My Beloved Son...." (Matthew 3:17) Later on he sent some of his disciples to check with the Lord Jesus if He is the One or would we still have to wait? Please explain.
From his mother's womb, the amazing and most unique St. John the Baptist knew our Lord Jesus Christ while He was in the womb of His mother, the Virgin Mary.
“But why is this granted to me, that the mother of my Lord should come to me? 44 For indeed, as soon as the voice of your greeting sounded in my ears, the babe leaped in my womb for joy” (Luke 1:43-44).
Never did St. John doubt our Lord Jesus Christ as the Messiah or His true Deity, but the time had come for the prophecies to be revealed. While in prison, St. John sent his disciples to Christ, not only for Him to reveal Himself to them, for He already knew Him, but knowing his disciples' loyalty to himself, they needed to continue on with Christ and be discipled unto Him. Therefore, Christ answered St. John's disciples' inquiry by revealing the prophecy made by Isaiah the prophet, signaling to St. John that indeed His ministry was underway.
”Then the eyes of the blind shall be opened, And the ears of the deaf shall be unstopped. 6Then the lame shall leap like a deer, And the tongue of the dumb sing. For waters shall burst forth in the wilderness, And streams in the desert. 7The parched ground shall become a pool, And the thirsty land springs of water; In the habitation of jackals, where each lay, There shall be grass with reeds and rushes” (Isaiah 35:5-7).
“Jesus answered and said to them, “’Go and tell John the things you have seen and heard: that the blind see, the lame walk, the lepers are cleansed, the deaf hear, the dead are raised, the poor have the gospel preached to them. And blessed is he who is not offended because of Me.’” (Luke 7:22-23).
At this moment, the Lord also added another revelation of prophecy by Malachi the prophet regarding St. John, further confirming his role as the one who was to prepare the way, beginning with repentance.
“’Behold, I send My messenger, And he will prepare the way before Me. And the Lord, whom you seek, Will suddenly come to His temple, Even the Messenger of the covenant, In whom you delight. Behold, He is coming,’says the LORD of hosts” (Malachi 3:1).
”This is he of whom it is written: ‘Behold, I send My messenger before Your face, Who will prepare Your way before You.’” (Luke 7:27).
Furthermore, Christ took this opportunity to praise St. John for his humility, obedience, and boldness in proclaiming the truth and in preparing the way for His coming, i.e., the coming of Christ, His ministry, and His plan of Salvation.
”’For I say to you, among those born of women there is not a greater prophet than John the Baptist; but he who is least in the kingdom of God is greater than he.’
29And when all the people heard Him, even the tax collectors justified God, having been baptized with the baptism of John. 30But the Pharisees and lawyers rejected the will of God for themselves, not having been baptized by him. 31And the Lord said, ’To what then shall I liken the men of this generation, and what are they like? They are like children sitting in the marketplace and calling to one another, saying:
‘We played the flute for you, And you did not dance; We mourned to you, And you did not weep.’ For John the Baptist came neither eating bread nor drinking wine, and you say, ‘He has a demon.’ The Son of Man has come eating and drinking, and you say, ‘Look, a glutton and a winebibber, a friend of tax collectors and sinners!’ But wisdom is justified by all her children.’’” (Luke 7:28-35).