Staring in the first Gospel of Matthew:
Matthew 1:1 The book of the generation of Jesus Christ, the son of David, the son of Abraham.
Matthew 4:4 But he answered and said, It is written, Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God.
Matthew 4:7 Jesus said unto him, It is written again, Thou shalt not tempt the Lord thy God.
Matthew 5:17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.
19 Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
Matthew 6:29 And yet I say unto you, That even Solomon in all his glory was not arrayed like one of these.
Matthew 8:11 And I say unto you, That many shall come from the east and west, and shall sit down with Abraham, and Isaac, and Jacob, in the kingdom of heaven.
Matthew 8:17 That it might be fulfilled which was spoken by Esaias the prophet, saying, Himself took our infirmities, and bare our sicknesses.
Matthew 9:27 And when Jesus departed thence, two blind men followed him, crying, and saying, Thou son of David, have mercy on us.
Matthew 10:6 But go rather to the lost sheep of the house of Israel.
Matthew10:15 Verily I say unto you, It shall be more tolerable for the land of Sodom and Gomorrha in the day of judgment, than for that city.
Matthew 11:10 For this is he, of whom it is written, Behold, I send my messenger before thy face, which shall prepare thy way before thee.
Matthew 11:23 And thou, Capernaum, which art exalted unto heaven, shalt be brought down to hell: for if the mighty works, which have been done in thee, had been done in Sodom, it would have remained until this day.
24 But I say unto you, That it shall be more tolerable for the land of Sodom in the day of judgment, than for thee.
Matthew 12:3 But he said unto them, Have ye not read what David did, when he was an hungred, and they that were with him;
Matthew 12:17 That it might be fulfilled which was spoken by Esaias the prophet, saying,
Matthew 12:23 And all the people were amazed, and said, Is not this the son of David?
Matthew 12:39 But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas:
40 For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.
41 The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonas; and, behold, a greater than Jonas is here.
42 The queen of the south shall rise up in the judgment with this generation, and shall condemn it: for she came from the uttermost parts of the earth to hear the wisdom of Solomon; and, behold, a greater than Solomon is here.
Matthew 13:14 And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:
Matthew 13:35 That it might be fulfilled which was spoken by the prophet, saying, I will open my mouth in parables; I will utter things which have been kept secret from the foundation of the world.
Matthew 15:1Then came to Jesus scribes and Pharisees, which were of Jerusalem, saying,
2 Why do thy disciples transgress the tradition of the elders? for they wash not their hands when they eat bread.
3 But he answered and said unto them, Why do ye also transgress the commandment of God by your tradition?
4 For God commanded, saying, Honour thy father and mother: and, He that curseth father or mother, let him die the death.
5 But ye say, Whosoever shall say to his father or his mother, It is a gift, by whatsoever thou mightest be profited by me;
6 And honour not his father or his mother, he shall be free. Thus have ye made the commandment of God of none effect by your tradition.
7 Ye hypocrites, well did Esaias prophesy of you, saying,
8 This people draweth nigh unto me with their mouth, and honoureth me with their lips; but their heart is far from me.
Matthew15:31 Insomuch that the multitude wondered, when they saw the dumb to speak, the maimed to be whole, the lame to walk, and the blind to see: and they glorified the God of Israel.
Matthew 16:4 A wicked and adulterous generation seeketh after a sign; and there shall no sign be given unto it, but the sign of the prophet Jonas. And he left them, and departed.
Matthew 17:3 And, behold, there appeared unto them Moses and Elias talking with him.
4 Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias.
Matthew 17:10 And his disciples asked him, saying, Why then say the scribes that Elias must first come?
11 And Jesus answered and said unto them, Elias truly shall first come, and restore all things.
12 But I say unto you, That Elias is come already, and they knew him not, but have done unto him whatsoever they listed. Likewise shall also the Son of man suffer of them.
Matthew19:4 And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female,
Matthew 19:8 He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so.
Matthew 19:17 And he said unto him, Why callest thou me good? there is none good but one, that is, God: but if thou wilt enter into life, keep the commandments.
18 He saith unto him, Which? Jesus said, Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness,
19 Honour thy father and thy mother: and, Thou shalt love thy neighbour as thyself.
Matthew 20:30 And, behold, two blind men sitting by the way side, when they heard that Jesus passed by, cried out, saying, Have mercy on us, O Lord, thou son of David.
Matthew 21:4 All this was done, that it might be fulfilled which was spoken by the prophet, saying,
5 Tell ye the daughter of Sion, Behold, thy King cometh unto thee, meek, and sitting upon an ass, and a colt the foal of an ass.
Matthew 21:9 And the multitudes that went before, and that followed, cried, saying, Hosanna to the son of David: Blessed is he that cometh in the name of the Lord; Hosanna in the highest.
Matthew 21:13 And said unto them, It is written, My house shall be called the house of prayer; but ye have made it a den of thieves.
Matthew 21:15 And when the chief priests and scribes saw the wonderful things that he did, and the children crying in the temple, and saying, Hosanna to the son of David; they were sore displeased,
Matthew 21:42 Jesus saith unto them, Did ye never read in the scriptures, The stone which the builders rejected, the same is become the head of the corner: this is the Lord's doing, and it is marvellous in our eyes?
Matthew 22:29 Jesus answered and said unto them, Ye do err, not knowing the scriptures, nor the power of God.
Matthew 22:31 But as touching the resurrection of the dead, have ye not read that which was spoken unto you by God, saying,
32 I am the God of Abraham, and the God of Isaac, and the God of Jacob? God is not the God of the dead, but of the living.
Matthew 22:36 Master, which is the great commandment in the law?
37 Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind.
38 This is the first and great commandment.
39 And the second is like unto it, Thou shalt love thy neighbour as thyself.
40 On these two commandments hang all the law and the prophets.
41 While the Pharisees were gathered together, Jesus asked them,
42 Saying, What think ye of Christ? whose son is he? They say unto him, The son of David.
43 He saith unto them, How then doth David in spirit call him Lord, saying,
44 The Lord said unto my Lord, Sit thou on my right hand, till I make thine enemies thy footstool?
45 If David then call him Lord, how is he his son?
46 And no man was able to answer him a word, neither durst any man from that day forth ask him any more questions.
I would say the Old Testament is still relevant according to Christ.