Blessed be the LORD: for he hath shewed me his marvellous kindness in a strong city.
Strong city. Yahweh Himself, with His almighty protection, is the "strong city" (Psalms 46:1; Psalms 46:11). Thus, this last verse of the third strophe corresponds to the first verse of the first strophe, Psalms 31:2 (cf. Jeremiah 18:1-23).