הלכה על ברכות 63:32

The proper order of prayer is to begin by praising God and only then to petition Him. We learn this from Moshe, who opened his prayer with words of praise, saying (Devarim 3:24), “Lord, God, You have begun to show Your servant Your greatness and Your mighty hand. What force is there in heaven or earth that can perform deeds and mighty acts as You do?” Only afterwards did Moshe plead, “Please let me cross [the Jordan] so that I may see the good land…” Based on this, Rav Simlai interprets, “One should always praise God first and afterwards pray” (Berakhot 32a). The primary application of putting praise before request is found in the berakhot of the Amida, for as previously mentioned (12:9), the first three berakhot open with words of praise and only later continue to the petitionary berakhot. However, even in the rest of one’s prayer, it is proper to open with words of praise, and that is the purpose of Pesukei De-zimra.