Notice how it also says, "Labour not for the meat which perisheth, but for that meat which endureth unto everlasting life"?
Salvation comes from believing and doing.
29. Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.
But, Jesus also said that belief on him is not enough. Neither did the apostles.
Doing the will of the Father is not just believing on the Promise through Christ, but also on doing the Will of the Father, as Jesus himself did.
25 And, behold, a certain lawyer stood up, and tempted him, saying, Master, what shall I do to inherit eternal life?
26 He said unto him, What is written in the law? how readest thou?
27 And he answering said, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind; and thy neighbour as thyself.
28 And he said unto him, Thou hast answered right: this do, and thou shalt live.
29 But he, willing to justify himself, said unto Jesus, And who is my neighbour?
30 And Jesus answering said, A certain man went down from Jerusalem to Jericho, and fell among thieves, which stripped him of his raiment, and wounded him, and departed, leaving him half dead.
31 And by chance there came down a certain priest that way: and when he saw him, he passed by on the other side.
32 And likewise a Levite, when he was at the place, came and looked on him, and passed by on the other side.
33 But a certain Samaritan, as he journeyed, came where he was: and when he saw him, he had compassion on him,
34 And went to him, and bound up his wounds, pouring in oil and wine, and set him on his own beast, and brought him to an inn, and took care of him.
35 And on the morrow when he departed, he took out two pence, and gave them to the host, and said unto him, Take care of him; and whatsoever thou spendest more, when I come again, I will repay thee.
36 Which now of these three, thinkest thou, was neighbour unto him that fell among the thieves?
37 And he said, He that shewed mercy on him. Then said Jesus unto him, Go, and do thou likewise.
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James 2:14 What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him?
15 If a brother or sister be naked, and destitute of daily food,
16 And one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit?
17 Even so faith, if it hath not works, is dead, being alone.
18 Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works.
19 Thou believest that there is one God; thou doest well: the devils also believe, and tremble.
20 But wilt thou know, O vain man, that faith without works is dead?
21 Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?
22 Seest thou how faith wrought with his works, and by works was faith made perfect?
23 And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness: and he was called the Friend of God.
24 Ye see then how that by works a man is justified, and not by faith only.
25 Likewise also was not Rahab the harlot justified by works, when she had received the messengers, and had sent them out another way?
26 For as the body without the spirit is dead, so faith without works is dead also. Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?font color=red