The first stage is his life in his mother's womb:
לְדָוִד ׀ בָּרֲכִי נַפְשִׁי אֶת־יְהוָה וְכָל־קְרָבַי אֶת־שֵׁם קָדְשֽׁוֹ׃
[A Psalm] of David. Bless, O my soul, the Lord and all that is within me, His holy name.
David then emerged into the atmosphere of the world and sang a song praising the entirety of Creation:
(כ) בָּרֲכוּ יְהוָה מַלְאָכָיו גִּבֹּרֵי כֹחַ עֹשֵׂי דְבָרוֹ לִשְׁמֹעַ בְּקוֹל דְּבָרֽוֹ׃
(20) Bless the Lord, O His angels, valiant in power, doing His word so as to heed the voice of His word.
(כא) בָּרֲכוּ יְהוָה כָּל־צְבָאָיו מְשָׁרְתָיו עֹשֵׂי רְצוֹנֽוֹ׃
(21) Bless the Lord, all His hosts; His ministers, that do His pleasure.
(כב) בָּרֲכוּ יְהוָה ׀ כָּֽל־מַעֲשָׂיו בְּכָל־מְקֹמוֹת מֶמְשַׁלְתּוֹ בָּרֲכִי נַפְשִׁי אֶת־יְהוָֽה׃
(22) Bless the Lord, all His works; In all places of His dominion; Bless, O my soul, the Lord.
David nursed from his mother's breast, his third world, and he looked upon her bosom and said a song of praise:
בָּרֲכִי נַפְשִׁי אֶת־יְהוָה וְאַל־תִּשְׁכְּחִי כָּל־גְּמוּלָֽיו׃
Bless, O my soul, the Lord, and do not forget not all His bounties.
He sang the fourth song when he witnessed, both in vision and in reality, the downfall of the wicked:
יִתַּמּוּ חַטָּאִים ׀ מִן־הָאָרֶץ וּרְשָׁעִים ׀ עוֹד אֵינָם בָּרֲכִי נַפְשִׁי אֶת־יְהוָה הַֽלְלוּ־יָֽהּ׃
(35) Let sinners cease out of the earth, and let the wicked be no more. Bless the LORD, O my soul. Hallelujah.
The fifth stage was when David looked upon the day of death:
בָּרֲכִי נַפְשִׁי אֶת־יְהוָה יְהוָה אֱלֹהַי גָּדַלְתָּ מְּאֹד הוֹד וְהָדָר לָבָֽשְׁתָּ׃
Bless O my soul, the Lord. O Lord my God, You are very great; You are clothed with glory and majesty.