If you are younger the age of 59 1/2, you cannot withdraw money from your 401(k) plan to buy your first house without  a 10 percent additional tax on early distributions from qualified retirement plans.

However, depending on the rules for your 401(k) plan, you might be able to borrow money from your 401(k) plan to buy your first home. Similiar to using the fund as a collateral. Interest and payment may vary but it seems to be worth looking into.