I don't think these verses deny the simple truth of John 6:47, belief for eternal life. John 6:47 doesn't say you must believe and repent and confess and be baptized for eternal life, it simply says believe. Should belief lead to all these things? Absolutely. But the simple one-line truth of John 6:47 is simply true.
Do not isolate and proof text Bible verses apart from the harmonious whole of the Bible. It is factual to state that a car will drive if one fills the tank with petrol, yet such a truism is moot if the car has no wheels. Likewise it is true that those who believe have everlasting life but belief in context is an obedient abiding in the light and thus walking as Jesus walked.
1Jn 2:3 And
hereby we do know that we know him, if we keep his commandments.
1Jn 2:4 He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
1Jn 2:5 But
whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him.
1Jn 2:6
He that saith he abideth in him ought himself also so to walk, even as he walked.
Anyone claiming to know Jesus Christ and yet is still in rebellion to God (ie. they do which they know is wrong) is a liar.
Many people wish to disconnect repentance as being a condition of salvation. It is quite unfortunate that this is so but just goes to show how easily the human mind processes information in a biased manner in order to placate feelings and desires.
The Bible is very clear in regards to this issue.
2Co 7:10 For
godly sorrow worketh repentance to salvation not to be repented of: but the sorrow of the world worketh death.
Paul clearly wrote that godly sorrow works repentance unto salvation. He did not write salvation works repentance unto eternal life. Salvation is a state of being "freed from sin" not a state of being "freed in sin." A prisoner is not free whilst still locked in prison nor is a slave free who remains in service to his slave master. Jesus came to redeem us FROM our sins and not to redeem us in them. Many people err in their thinking and thus easily swallow a notion where they are redeemed in their sins thus setting them up to believe they are saved when they are not. If Satan can convince someone that are in fact saved when they are not then that individually is effectively immunised against the genuine salvation experience because they will not perceive what it is and will not seek it out via approaching God in the correct manner.
Mat_4:17 From that time
Jesus began to preach, and to say,
Repent: for the kingdom of heaven is at hand.
Mat_9:13 But go ye and learn what that meaneth, I will have mercy, and not sacrifice: for I am not come to call the righteous, but
sinners to repentance.
Mar_1:4 John did baptize in the wilderness, and preach the
baptism of repentance for the remission of sins.
Mar_1:15 And saying, The time is fulfilled, and the kingdom of God is at hand:
repent ye, and believe the gospel.
Mar_2:17 When Jesus heard it, he saith unto them, They that are whole have no need of the physician, but they that are sick: I came not to call the righteous, but
sinners to repentance.
Mar_6:12 And they went out, and preached that
men should repent.
Luk_3:3 And he came into all the country about Jordan, preaching the
baptism of repentance for the remission of sins;
Luk_13:3 I tell you, Nay: but,
except ye repent, ye shall all likewise perish.
Luk_13:5 I tell you, Nay: but, except ye repent, ye shall all likewise perish.
Luk_3:8
Bring forth therefore fruits worthy of repentance, and begin not to say within yourselves, We have Abraham to our father: for I say unto you, That God is able of these stones to raise up children unto Abraham.
Luk_5:32 I came not to call the righteous, but
sinners to repentance.
Luk_15:7 I say unto you, that likewise joy shall be in heaven over
one sinner that repenteth, more than over ninety and nine just persons, which need no repentance.
Luk_24:47 And that
repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.
Act_2:38 Then Peter said unto them,
Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Act 3:19
Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord;
Act_11:18 When they heard these things, they held their peace, and glorified God, saying, Then hath God also to the Gentiles granted
repentance unto life.
Act_13:24 When John had first preached before his coming the
baptism of repentance to all the people of Israel.
The baptism of repentance and believing in Jesus go hand in hand. One cannot believe in Jesus (a saving belief) unless they repent and thus forsake their rebellion. This is why James taught that faith without works is dead and that the devils faith is belief without any outward transformation in conduct.
Act_19:4 Then said Paul, John verily baptized with
the baptism of repentance, saying unto the people,
that they should believe on him which should come after him, that is, on Christ Jesus.
Act_20:21 Testifying both to the Jews, and also to the Greeks, r
epentance toward God, and faith toward our Lord Jesus Christ.
Act_26:20 But shewed first unto them of Damascus, and at Jerusalem, and throughout all the coasts of Judaea, and then to the Gentiles,
that they should repent and turn to God, and do works meet for repentance.
2Pe_3:9 The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but
that all should come to repentance. 
