"And he commanded them saying 'Thus shalt thou say to my lord Eisav: So saith your servant Yaakov. I am sojourned with Lavan from before until now.'" (Bereshis 32:5)
Rashi: Sojourned - I have not become a prince or an important person, rather just a sojourner. Thus it is not worth hating me over the blessing your father gave me: 'Be thou a lord over your brethren' because it wasn't fulfilled in me. Another interpretation: garti (sojourned) in gematria is 613, that is to say: With the wicked Lavan I sojourned (garti) but I kept all 613 (taryag) commandments and I didn't learn from his wicked deeds.
The Sifsei Chachamim on this Rashi note that Yaakov Avinu had an interesting problem in deciding what to tell Eisav upon returning to the Land of Israel. On one hand, he wanted to present himself humbly and the best way to do that was to note that he hadn't really achieved the blessing of greatness Yitzchak Avinu had granted him. That would have the effect of mollifying Eisav's anger. On the other hand, by telling him that he hadn't achieved greatness, Eisav could turn around and say "Well hang on, it said that if you keep the Torah you'll achieve greatness. If you are still not great, that means you didn't keep the Torah and when you don't, my blessing from father is that I get to rule over you!" (Bereshis 27:40) Thus Yaakov was forced to tell two contradictory statements - yes, I kept the entire Torah which means you cannot harm me, but don't be angry with me because in the end I didn't achieve greatness anyway.
The Kli Yakar, on the other hand, doesn't feel that Rashi's two suggestions are contradictory. He interprets that what Yaakov was telling Eisav was that the reason he hadn't become great was not because Yitzchak's blessing had failed to manifest itself for him but because he was never meant to get that blessing in the first place. His deception, as it were, had not availed him anything. Despite keeping the 613 mitzvos, he had not achieved glory in This World because that beracha had been meant for Eisav and it didn't matter that Yitzchak had said it to him. A person can't touch that which is meant for his fellow. Thus he was assuring Eisav: don't worry, you clearly got the blessing. It turns out I didn't take anything from you because despite keeping all 613 commandments, the blessing wound up in your portion anyway and so you have no reason to be mad at me. Thus there is no contradiction and Rashi's two suggestions go together perfectly.
The Sifsei Chachamim then notes an interesting problem - never mind that he married two sisters, something forbidden by the Torah. Even ignoring that, Yaakov Avinu had been in chutz l'aretz for 20 years. There are many mitzvos that can only be performed in the Land of Israel. Furthermore, there are mitzvos that can only be performed by the entire community, like building the Temple and setting up a king. How could Yaakov say that he had kept all 613 mitzvos?
He thus brings from the Divre David the well-known principle in halacha that when one studies the laws of sacrifices, it is considered like he has offered them. So too with Yaakov - since he had studied the entire Torah assiduously, it was like he had kept all 613 mitzvos.
The Chasam Sofer looks at it from a different, more grammatical angle. According to Rashi, Yaakov suggested "Taryag mitzvos shamarti" - I have guarded 613 commandments- instead of the more logical "Taryag mitzvos kiyamti" - I have fulfilled 613 commandments. He notes one use of the root shamar means to put something aside and keep watch over it, as in next week's parasha: "And his father shamar the matter." (37:11) In other words, by keeping the Torah and all its 613 commandments in mind, even though he couldn't actually fulfill them, he had kept them - shamarti - in a positive manner.
However, it seems to me there is a different way to connect Rashi's two suggestions. The truth is that a Torah lifestyle does set one apart from surrounding society. Its values, rituals and principles are different from other religions and especially from secular society. The underlying reason for this is that the committed Jew understands that the ikkar in the life of his soul is not here in This World which is just a temporary stay but rather in the Olam Haba. We are all sojourners in this world, it's just that some of us realize it more than others.
This would explain something which is difficult to understand about Lavan's relationship with Yaakov. Yes, Lavan was a deceiver interested in material gain. However, his behaviour towards his nephew is still not understandable. After openly admitting that Yaakov has become his meal ticket to prsoperity (30:27) it would make sense that he would everything he could to make him happy and want to stay with him. He should have treated him with honour, elevated him to the top of his household but instead spent the next six years driving a wedge between them, cheating and harrassing him repeatedly. Who tries to drive away the golden goose?
Yaakov's fixation on the mitzvos however would have caused him to be seen in a different light. When Yaakov announced his intention to eventually leave and return home, Lavan knew that nothing he could offer him would change his mind. Yaakov wasn't looking for independence or greater prosperity. Succeeding in this world was of minimum meaning to him. He would return home no matter what because this was his holy destiny. Thus there was no point in trying to absorb him into "the family" and the only thing left was to fleece him for all he could.
And how could Lavan be sure that no matter what he did, Yaakov wouldhold by the terms of any deal they made? Rav Joseph Hertz, in his Chumash, notes that when Yaakov is listing all his grievances before his uncle at the end of their relationship (31:36-42) he isn't merely spouting off about what he feels he has been cheated of over the last six years. Rather he is quoting his rights under the Code of Hammurabi in terms of how he had fuflilled all his obligations as a worker while Lavan had shirked all of his as an employer. One of the things b'nei Noach are commanded to do is a establish a system of laws to run society. Having found himself in a society governed by Hammurabi's code, Yaakov had kept its rules perfectly even thought Lavan hadn't.
Why? Because Yaakov's desire to be close to God elevated his behaviour to one of perfection even in the face of duplicitous opposition. There was a principle at stake - one of remaining true to God's expectations of him.
Yaakov Avinu, because of his study and depth of understanding of Torah, realized this completely. He had remained separate from Lavan because of insistence on following the path of God, not of base materialism his uncle had chosen. It was specifically because he had kept the 613 mitzvos that he had failed to become a prince and important man in Aram. What would have been the benefit of that to someone whose eyes are on his soul returning to God, not on prospering in this material reality?
Therefore he was telling Eisav that there was nothing to fear and no reason to be angry. Despite having been immersed in the superficial civlization of Lavan, he had rejected that which Yitzchak's blessing might have brought him in a material sense. Only keeping the 613 mitzvos and maintaining his connection to God had been important to him.