If you truly believe in Him, receive him as Savior, then, yes, you WILL do as he commands. Jesus said, "If you love me you will obey my commandments." We are indwelt with the Holy Spirit, reborn as children of God, and the new nature seeks after goodness and light. But, here's the difference, one does not "do" or "obey" in order to BE saved, but because we ARE saved. "He who has the Son has life and he has not the Son of God has NOT life, but the wrath of God abides on him." (John 3:17). By faith is how we are saved. By our works, our fruit, is how we demonstrate our faith. Faith that does not demonstrate good fruit is a dead faith, one that is not genuine. It should be obvious, though, that works are an outward sign of an inward change.
As far as "unless you eat of my flesh and drink of my blood, you shall not have life within you", I fully believe that. But I also believe that when we receive him, believe on him, we ARE consuming Him. Look what he actually said as recorded by John 6:27-29
Do not work for food that spoils, but for food that endures to eternal life, which the Son of Man will give you. For on him God the Father has placed his seal of approval.” Then they asked him, “What must we do to do the works God requires?” Jesus answered, “The work of God is this: to believe in the one he has sent.”
Then he added, verses 35-40:
Then Jesus declared, “I am the bread of life. Whoever comes to me will never go hungry, and whoever believes in me will never be thirsty. But as I told you, you have seen me and still you do not believe. All those the Father gives me will come to me, and whoever comes to me I will never drive away. For I have come down from heaven not to do my will but to do the will of him who sent me. And this is the will of him who sent me, that I shall lose none of all those he has given me, but raise them up at the last day. For my Father’s will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise them up at the last day.”
See, what you don’t realize is that you’ve come all the away around to the position that the Catholic Church was arguing in refutation of Luther. Luther was charged with making the following statements:
In every good work the just man sins.
A good work done very well is a venial sin.
No one is certain that he is not always sinning mortally, because of the most hidden vice of pride.
Great is the error of those who approach the sacrament of the Eucharist relying on this, that they have confessed, that they are not conscious of any mortal sin, that they have sent their prayers on ahead and made preparations; all these eat and drink judgment to themselves.
As long as we wish to confess all sins without exception, we are doing nothing else than to wish to leave nothing to God’s mercy for pardon.
By no means may you presume to confess venial sins, nor even all mortal sins, because it is impossible that you know all mortal sins.
Contrition, which is acquired through discussion, collection, and detestation of sins, by which one reflects upon his years in the bitterness of his soul, by pondering over the gravity of sins, their number, their baseness, the loss of eternal beatitude, and the acquisition of eternal damnation, this contrition makes him a hypocrite, indeed more a sinner.
Thus, the pope wrote of Luther as he excommunicated him:
Nevertheless Martin himself—and it gives us grievous sorrow and perplexity to say this—the slave of a depraved mind, has scorned to revoke his errors within the prescribed interval and to send us word of such revocation, or to come to us him-self; nay, like a stone of stumbling, he has feared not to write and preach worse things than before against us and this Holy See and the Catholic faith, and to lead others on to do the same.