Public policy mandates STRICT requisites in declaring law unconstitutional

Now, petitioner is challenging the constitutionality of Section 7 of Act No. 3135, as amended. He avers that Section 7 violates the due process clause because, by the mere filing of an ex parte motion in the proper cadastral court, the purchaser in a foreclosure sale is allowed to obtain possession of the foreclosed property during the redemption period.
The Court of Appeals ruled that petitioners attempt to challenge the constitutionality of Section 7 of Act No. 3135, as amended, constitutes a collateral attack that is not allowed. The Supreme Court fully agrees with the appellate courts ruling. For reasons of public policy, the constitutionality of a law cannot be attacked collaterally. (G.R. No. 165142; December 10, 2007)