The fronted 1cs personal pronoun אני marks a change in topic, viz. redirecting the attention from God in general and various circumstances involving “ups and downs” in particular to some personal experience of the speaker.
 Particular attention is drawn to the poet's certainty and the duration for how long his peaceful times will last through the use of בל (“no/never”) and לעולם (“forever”).
 Double fronting: Yahweh is fronted for topic re-activation (or it may simply be a vocative), whereas בִּרְצוֹנְךָ is fronted for constituent focus, which confirms the means (or manner) in which God acted, making the poet stable and at "ease" (cf. v. 7). The preposition בְּ aids in communicating this expression of means/manner.
 There are textual problems with this verse for it literally reads: you made me stand as/to my mountain strength. I understand the לְ as indicating the state of existence in which the poet now stands, being the recipient of God's favor and see this fact as overriding the lack of construct relationship between mountain and strength (because of the 1cs suffix) and assume that there was meant to be one.
 In Hebrew, the literal expression is your face (פניך), which idiomatically expresses your presence.
 Petrified as been chosen to gloss נבהל because it accurately expresses the terror that this word connotes, yet at the same time maintains the image of the mighty mountain that the poet claims to have been just made into. Thus, ironically, in God's presence the poet is as strong as a mountain, yet in his absence he is scared stiff, stone cold—petrified.