John 10:7

10:7 So Jesus said to them again, “I tell you the solemn truth, I am the door for the sheep.

John 3:3

3:3 Jesus replied, “I tell you the solemn truth, unless a person is born from above, he cannot see the kingdom of God.”

John 3:11

3:11 I tell you the solemn truth, we speak about what we know and testify about what we have seen, but you people do not accept our testimony.

John 8:34

8:34 Jesus answered them, “I tell you the solemn truth, everyone who practices sin is a slave of sin.

John 8:51

8:51 I tell you the solemn truth, if anyone obeys my teaching, he will never see death.”

John 10:1

Jesus as the Good Shepherd

10:1 “I tell you the solemn truth, the one who does not enter the sheepfold by the door, but climbs in some other way, is a thief and a robber.

John 13:16

13:16 I tell you the solemn truth, the slave is not greater than his master, nor is the one who is sent as a messenger greater than the one who sent him.

John 13:20-21

13:20 I tell you the solemn truth, whoever accepts the one I send accepts me, and whoever accepts me accepts the one who sent me.”

13:21 When he had said these things, Jesus was greatly distressed in spirit, and testified, “I tell you the solemn truth, one of you will betray me.”

John 13:38

13:38 Jesus answered, “Will you lay down your life for me? I tell you the solemn truth, the rooster will not crow until you have denied me three times!