A law that states it shall take effect on the day of its approval becomes effective from the very first moment of that day, as the law does not recognize fractions of a day for the purpose of determining a statute's effectivity.

The case arose from a naturalization proceeding governed by the then-existing law. A new statute, Republic Act No. 530, was enacted, fundamentally altering the naturalization process by mandating that a decision granting citizenship would only become executory after a two-year waiting period from its promulgation. The dispute centered on whether this new law applied to the respondent, Si Kee, whose naturalization decision was set to become final and executory on the very same day that R.A. 530 was approved by the President. The core of the conflict was the interpretation of the law's effective date and its applicability to cases that were on the cusp of finality.

• On May 15, 1950, the Court of First Instance (CFI) of Rizal issued a supplementary decision granting the petition for naturalization of respondent Si Kee.
• The Solicitor General was notified of this decision on May 16, 1950, giving him until June 15, 1950, to file an appeal under the old law.
• No appeal was filed, and the decision was set to become final and executory on June 16, 1950.
• On June 16, 1950, the President of the Philippines approved Republic Act No. 530.
• Section 1 of R.A. 530 provides that no decision granting an application for naturalization shall become executory until after two years from its promulgation.
• Section 4 of R.A. 530 states that the law shall take effect upon its approval and shall apply to pending cases and cases where the applicant has not yet taken the oath of citizenship.
• On July 12, 1950, despite the Solicitor General's opposition, the CFI issued an order scheduling Si Kee's oath-taking for July 18, 1950.
• The Solicitor General filed a petition before the Supreme Court to nullify this order, arguing that R.A. 530 applied to Si Kee's case.

• The petitioner, Republic of the Philippines, argued that the lower court was not authorized to order the oath-taking of Si Kee because Republic Act No. 530 was already in effect.
• R.A. 530 took effect on June 16, 1950, the same day the CFI's decision was supposed to become final, and its provisions are applicable to Si Kee's case as he had not yet taken the oath.
• The law became effective from the first minute of June 16, 1950, meaning the CFI decision never became executory under the old law.
• Because the new law was in force before the decision became final, Si Kee did not acquire any vested right under the old naturalization law.

• The respondent, Si Kee, contended that the CFI's supplementary decision had become final and executory before R.A. 530 came into force.
• He argued that R.A. 530 was approved by the President at midnight on June 16, 1950, and therefore, the decision had already become final earlier that day.
• The effectivity of the law should be counted from the precise moment of the President's signature, not from the beginning of the day of its approval.
• Consequently, R.A. 530 was not applicable to his case.

• Procedural Issues:
  • N/A
• Substantive Issues:
  • Whether a law that takes effect "upon its approval" becomes effective from the first moment of the day of approval or from the precise time of the President's signature.
  • Whether Republic Act No. 530 is applicable to a naturalization case where the decision was set to become final on the same day the new law was approved.

• Procedural:
  • N/A
• Substantive:
  • The Supreme Court granted the petition of the Republic. It ruled that a law which is to take effect on the day of its approval becomes effective from the first moment of that day. The Court reasoned that public policy demands certainty in the effectivity of laws, which would be undermined if effectivity depended on the "insecure memory of men" and oral evidence regarding the exact time of the President's signature. The legislature's specification of the day, not the hour or minute, indicates its intent for the law to be effective for the entire day. Therefore, R.A. 530 was in full force and effect from the very beginning of June 16, 1950. As the CFI's decision in favor of Si Kee was only to become final on that same day, the new law's requirements, including the two-year waiting period, applied to him. The lower court's order scheduling his immediate oath-taking was therefore improper and issued without authority.

• Statutory Construction (Effective Date of Laws) — A statute that is to take effect on the day of its approval is deemed effective from the first moment of that day. The law does not recognize fractions of a day in determining the effectivity date. This doctrine was applied to establish that R.A. 530 was in force for the entire day of June 16, 1950, thereby intercepting the finality of the respondent's naturalization decision under the previous law.
• Retroactive Application of Remedial Statutes — R.A. 530 was applied to the respondent's case based on its express provision in Section 4, which made it applicable to cases pending in courts and to those where the applicant had not yet taken the oath of citizenship. The Court enforced this clear legislative intent, as Si Kee had not yet taken his oath when the law became effective.

• "La ley entró en vigor desde el primer minuto del día en que fue aprobada, y no en el preciso momento en que, según las pruebas orales del recurrido, fue firmada por el Presidente." (The law took effect from the first minute of the day it was approved, and not at the precise moment when, according to the oral evidence of the respondent, it was signed by the President.)
• "Razones poderosas de orden público exigen que no dependa de la insegura memoria de los hombres la fijación del momento de la aprobación de la ley; por eso, la Legislatura señala el día—no la hora ni el minuto—del comienzo de su vigencia para no estar sujeta a pruebas orales." (Powerful reasons of public order demand that the determination of the moment of a law's approval not depend on the insecure memory of men; for this reason, the Legislature indicates the day—not the hour or the minute—of the beginning of its effectivity so as not to be subject to oral evidence.)

• Republic Act No. 530, Section 1 — Cited as the statutory basis for the new requirement that a decision granting naturalization shall not become executory until after two years from its promulgation.
• Republic Act No. 530, Section 4 — Cited as the provision governing the law's effectivity ("upon its approval") and its applicability to pending cases where the applicant had not yet taken the oath of citizenship.
• Article 56 of the Registration Law (Ley de Registro) — Mentioned by the Court as an example of a law where the precise time (hour and minute) is required to be noted, arguing that if Congress had intended such precision for R.A. 530, it would have explicitly stated so.