31 And they were debating with themselves, saying, "If we say, 'From heaven,' He will say, 'Why then did you not believe him?'
Mark 11:31 Cross References - CAB
Matthew 11:7-14
7 Now as these men were going, Jesus began to say to the crowds concerning John: "What did you go out into the wilderness to see? A reed shaken by the wind?
8 But what did you go out to see? A man clothed in soft garments? Indeed, those who wear soft garments are in kings' houses.
9 But what did you go out to see? A prophet? Yes, I say to you, and far more than a prophet.
10 For this is he about whom it is written: 'Behold, I send My messenger before Your face, who will prepare Your way before You.'
11 "Assuredly I say to you, among those born of women there has not risen one greater than John the Baptist; but he that is least in the kingdom of heaven is greater than he.
12 And from the days of John the Baptist until now the kingdom of heaven suffers violence, and violent men seize it.
13 For all the prophets and the law prophesied until John.
14 And if you are willing to receive it, he is Elijah, the one who is about to come.
Matthew 21:25-27
25 The baptism of John--where was it from? From heaven or from men?" And they were arguing among themselves, saying, "If we say, 'From heaven,' He will say to us, 'Why then did you not believe him?'
26 "But if we should say, 'From men,' we fear the crowd, for all consider John as a prophet."
27 So they answered Jesus and said, "We do not know." And He said to them, "Neither will I tell you by what authority I do these things.
Matthew 21:31-32
31 Which of the two did the will of his father?" They said to Him, "The first." Jesus said to them, "Assuredly I say to you, that tax collectors and harlots enter the kingdom of God before you.
32 For John came to you in the way of righteousness, and you did not believe him; but tax collectors and harlots believed him; but you, having seen, did not repent afterwards, that you might believe him.
John 1:15
15 John testified concerning Him and has cried out, saying, "This was He of whom I said, 'He who comes after me, has come to be before me, because He was before me.' "
John 1:29
29 The next day he saw Jesus coming toward him, and said, "Behold! The Lamb of God who takes away the sin of the world!
John 1:34
34 "And I have seen and have testified that this is the Son of God."
John 1:36
36 And looking at Jesus as He was walking, he said, "Behold the Lamb of God!"
John 3:29-36
29 "He who has the bride is the bridegroom; but the friend of the bridegroom, who stands and hears him, rejoices greatly because of the voice of the bridegroom. Therefore my joy has been fulfilled.
30 He must increase, but I must decrease.
31 He who comes from above is above all; he who is from the earth is earthly and speaks of the earth. He who comes from heaven is above all.
32 And what He has seen and heard, that He testifies; and no one receives His testimony.
33 He who receives His testimony has certified that God is true.
34 For He whom God has sent speaks the words of God, for God does not give the Spirit by measure.
35 The Father loves the Son, and has given all things into His hand.
36 He who believes in the Son has eternal life; and he who does not believe the Son will not see life, but the wrath of God abides on him."