Defendant appeals from his conviction of possession of marijuana upon a trial to tRe District Court of Weber County. The complaint was filed January 18, 1969, charging the commission of the offense on the previous day, January 17. The various proceedings in the case, including the disposition of certain motions prior to trial, culminated over a year later in the defend- - ant being found guilty upon the trial held on May 26, 1970. On June 22, 1970, he was sentenced to an indeterminate term in the State Prison for not less than five years, the statutory penalty in effect at the time of the commission of the offense. Meanwhile, the 1969 Legislature, in S.L. U.1969, Ch. 170, § 13, amended Sec. 58-13a-44, U.C.A.19S3, reducing the penalty for that offense to a maximum of six months in the county jail. This statute became effective May 13, 1969, and thus before the trial and judgment.
Defendant contends that he was entitled to the benefit of the lesser statutory penalty in effect at the time of trial, judgment and sentence, rather than the more severe penalty which was in effect at the time the offense was committed.
In opposing that contention, the State places reliance on State v. Miller.1 The defendant was convicted of issuing a check against insufficient funds and had been, on April 7, 1969, sentenced to the term then prescribed by law of not more than five years in the State Prison. Thereafter, on May 13, 1969, there became effective Chapter 239, § 11, S.L.U.1969 (codified as 76-20-11, U.C.A.1953), reducing the term to six months. On appeal to this court, the defendant claimed the benefit of the reduced penalty, which claim we rejected. The significant difference between that case and the instant one is that in the Miller case the trial and conviction had been completed prior to the effective date of the amended statute, and the judgment and sentence were imposed in accordance with the statutory penalty in effect at that time.
*394By way of contrast with the Miller case, and consistent with the conclusion we reach herein, the later case of Belt v. Turner 2 involved the same change of statute reducing the penalty as to fraudulent checks. The court held that the defendant was entitled to the benefit of the reduced penalty, pointing out that the statute had become effective before the sentence was imposed, and that
* * * the judge followed the law in force and effect at that time.
But commented with respect to situations such as the Miller case that:
As to those defendants who were sentenced prior to the amendment, the statute gives no aid.
There are several considerations which in our minds tend to support our conclusion that where an enactment reducing the penalty for an offense has become effective prior to the conviction, a defendant is entitled to the benefit thereof by having penalty imposed in accordance with the law at the time of the sentence.3 The first of these is that it is the prerogative of the legislature, expressing the will of the people, to fix the penalties for crimes; and the courts should give effect to the enactment and the effective date thereof as so declared.4 There are some other fundamental principles engrained in our law which, though not directly controlling on the problem at hand, are generally in harmony with the policy considerations which lead to the conclusion we have reached herein. One of these is that to insist on the prior existing harsher penalty is a refusal to accept and keep abreast of the process which has been continuing over the years of ameliorating and modifying the treatment of antisocial behavior by changing the emphasis from vengeance and punishment to treatment and rehabilitation.5 In the same tenor are the time-honored rules of the criminal law generally favorable to one accused of crime: that in case of doubt or uncertainty as to the degree of crime, he is entitled to the lesser; and correlated thereto: that as to an alternative between a severe or a lenient punishment, he is entitled to the latter.6
*395We have reached our conclusion herein in awareness of Section 68-3-5, U.C.A. 1953:
The repeal of a statute does not * * * affect any right which has accrued, any duty imposed, any penalty in-ctirredj or any action or proceeding commenced under or by virtue of the statute repealed. (Emphasis added.)
The only way that statute can apply to the problem here involved, as to the appropriate sentence for the offense, would be through its provision that “The repeal of a statute does not * * * affect * * * any penalty incurred. * * * ” Inasmuch as no penalty is incvirred until the defendant is convicted, judgment entered and sentence imposed, that statute does not affect the propriety of doing so in accordance with the law as it exists at that time.
Upon the basis of what we have said above, we reaffirm our adherence to the principle set forth in the Miller and Belt cases referred to above: In the former : that if a statute reducing a penalty has not become effective until after the conviction and sentence, the sentence, imposed in accordance with the law in effect at the time thereof, should stand. In the latter: If the statute reducing the penalty has become effective before the sentence, as in this case, the defendant is entitled to the lesser penalty as provided by the law at the time of the judgment and sentence.
Defendant also assigns error in admitting in evidence the marijuana upon which the conviction is based. His contention is that the evidence was obtained by an “unreasonable search and seizure.”7 This is not the frequently confronted issue of a search without a warrant. It is not disputed that there was a duly issued search warrant, valid on its face. Defendant attempts to go behind that and attack the sufficiency of the affidavit upon which the warrant was predicated. As a basis for his belief that the illegal drug would be found on the premises, the affidavit of the police officer stated that an informer had purchased marijuana on several occasions from the defendant at the latter’s residence and had turned it over to the police.
In regard to the sufficiency of the affidavit and the issuance of a search warrant thereon: it is not necessary that the affiant have certain knowledge of the *396commission of crime or of the location of evidence incident thereto. It is only required that there be sufficient knowledge of the probability thereof that a person of reason and prudence would act thereon.8 When an affidavit setting forth such information is presented to a magistrate, it is his duty and prerogative to determine the sufficiency of the affidavit. In forming that judgment he is allowed considerable latitude of discretion, which should not be disturbed unless he was clearly in error, a circumstance which does not exist here.
The conviction is affirmed. The case is remanded for the imposition of sentence, which, in accordance with the views herein expressed, must not exceed six months in the county jail; and the defendant is to have credit on said sentence for any time he may have already served.
TUCKETT, and ELLETT, JJ., concur.. 24 Utah 2d 1, 464 P.2d 844.
. 25 Utah 2d 230, 479 P.2d 791, on rehearing, 25 Utah 2d 380, 483 P.2d 425.
. For cases discussing this problem and ruling in accordance with our holding herein, see: In re Falk, 64 Cal.2d 684, 51 Cal.Rptr. 279, 414 P.2d 407 (1966); In re Ring, 64 Cal.2d 450, 50 Cal.Rptr. 530, 413 P.2d 130 (1966); In re Estrada, 63 Cal.2d 740, 48 Cal.Rptr. 172, 408 P.2d 948 (1965); In re Fink, 67 Cal.2d 692, 63 Cal.Rptr. 369, 433 P.2d 161 (1967); State v. Pardon, 272 N.C. 72, 157 S.E.2d 698; and Sec. 21 Am.Jur. 2d 543 and cases there cited.
. State v. Mulcare, 189 Wash. 625, 66 P. 2d 360; Morgan v. Devine, 237 U.S. 632, 35 S.Ct. 712, 59 L.Ed. 1153.
. See discussion in In re Estrada, footnote 3 above.
. As we said in Ringwood v. State, 8 Utah 2d 287, 333 P.2d 943, in awareness of *395Secs. 68-3-2 and 76-1-2, U.C.A.1953, that a statute imposing a penalty must do so with clarity and definiteness and, “ * * * in ease of alternative choices, he [the defendant] can comply by selecting the one which is the least burdensome or least offensive to him”; see Sec. 77-31-5, U.C.A.1953; and also see O’Day v. People, 114 Colo. 373, 166 P.2d 789; Davis v. Riedman, N.D., 114 N.W.2d 881; cited in support of text at 21 Am.Jur.2d 544 that when penalty provision is susceptible of different interpretations defendant is entitled to most favorable.
. Art I, Sec. 14, Utah Constitution; 77-54-3, U.C.A.1953; Amendment VI, U.S. Constitution.
. The facts sustain the validity of the warrant see Spinelli v. United States, 393 U.S. 410.