In his commentary on Vayetzei (published in The Torah Anthology: Yalkut Me'am Lo'ez, translated by Rabbi Aryeh Kaplan; also available online), the Me'am Lo'ez notes that traditional commentary broadens Jacob's vow in the following ways:

[I]f God will be with me, keeping all his promises, so that I will not lack anything. And if I return in peace, innocent of sin, not influenced by Laban. If I am protected from spreading malicious gossip, from gazing at strange women and listening to them sing (since this is tantamount to lewdness), from publicly embarrassing another (which is considered like murder), and from purposely ignoring the poor (which is also like bloodshed). If Your name is associated with me from the beginning to the end, that none of my offspring should be unworthy, then I accept upon myself that this stone which I have erected as a monument will become God's Temple. Of all that You give me, I will set aside a tithe to You.

At first glance, this seems to make the vow even more conditional. Now it seems that Jacob is making his promise contingent not only on God remaining with him in his journey, ensuring his food and clothing, and watching over him unil he is safely home again -- but also on God protecting him from a series of malicious actions (spreading gossip, embarrassing others, ignoring the poor) which seem entirely within Jacob's control. Why should he need to hang his vow on whether or not God protects him from his own misdeeds -- aren't those misdeeds choices he himself will make?

Well, yes and no. The tradition presumes that while each of us is able to choose her or his actions freely, it also presumes that one's choices, and one's life, are continually caught between one's yetzer ha-tov (good inclination) and yetzer ha-ra (evil or chaotic inclination.) Jacob makes his vow conditional not because he doubts God, but because he doubts himself -- he knows that he may fall into patterns of wrong or petty behavior, and he wants God's help in holding up his own side of the bargain.

But why does he frame the vow as an "if...then" statement? What's iffy about it? Jacob's vision showed him clearly that God was present in that place, and God promised to stick with him wherever he might go. So when he says "If God remains with me," he can't be articulating concern that God might actually abandon him. There is no place where God is not, and God's commitment to him is clear.

Maybe what he's really saying is, "If I am able to remain conscious of God's presence with me; if I can awaken myself to God's protection as I journey...then I will be able to fully commit myself to connection with God." The vow, in other words, is a statement primarily about Jacob: his limitations, his hopes and fears, and the kind of covenantal partner he hopes, with God's help, to be.

The Me'am Lo'ez has much to say on the subject of vows:

Actually, it is not good to be too quick to make vows. From this story of Jacob, however, we learn that when a person is in trouble, it is a good deed to pledge money for charity or make a vow to study Torah.

The Torah therefore says, "Jacob made a vow, saying (lemor)." As a general rule, wherever the Torah uses the expression "lemor," it indicates that the statement was meant to be told to others. Since no one else was present, to whom should Jacob's message be conveyed? The Torah alludes to the fact that Jacob's statement was meant to teach a lesson to all generations: in a time of trouble one may make vows to do good.

Although one does not actually do anything when he makes a vow, the merit of the good deed he intends to do protects him in advance and rescues him from trouble.

I wouldn't be so sure that making a vow doesn't actually "do" anything. To be sure, no visible outward change arises. If I were to vow today to exercise regularly in the month of December, or to daven with greater kavvanah in shul this Shabbat, or to hand a dollar to the Salvation Army bell-ringer every time I enter the grocery store, there would be no noticeable change in the fabric of my world. (And, by the same token, were I to break any of those vows, it's likely no one would notice, much less call me on it.)

But when we make promises, we change ourselves in subtle ways. This is why Jewish tradition takes vows so seriously. Our vows say something about who we are, and who we hope to become. When we make vows we can't, or don't, fulfil, a kind of intangible detritus settles in our hearts. (This is why the Kol Nidre prayer, and the full experience of Yom Kippur, can be so powerful -- they allow us to clean our emotional and spiritual filters of a year's worth of lapsed promises, to each other and to ourselves, so that divine abundance can flow freely into our lives again.)

In any event, though I quibble with his assertion that making vows doesn't "do" anything, I like the Me'am Lo'ez's argument that when a person is in trouble, it is good to pledge money for tzedakah or to make a vow to study Torah. He knows that when we make promises that we know will make a difference, we want to live up to them. That our vows shape our way of being in the world.

Like Jacob, we are all prone to losing sight of God's presence on our journeys. But if his vow is meant to serve as an example to us, maybe it can inspire us toward the heights he hoped for. If we can remember that God is with us; if we can muster gratitude for the multitude of blessings in our lives; then we, too, can lay claim to the Source of All as our God. And then every stone we encounter can be a place of connection with the Holy Blessed One; and we will be able to set aside a tithe from the rich gifts God has given us, both physical and spiritual, to give back to the wide and wonderful world.