An offering and a sacrifice to God (prosphoran kai thusian tōi theōi). Accusative in apposition with heauton (himself). Christ’s death was an offering to God “in our behalf” (huper hēmōn) not an offering to the devil (Anselm), a ransom (lutron) as Christ himself said (Mat 20:28), Christ’s own view of his atoning death.
For an odour of a sweet smell (eis osmēn euōdias). Same words in Phi 4:18 from Lev 4:31 (of the expiatory offering). Paul often presents Christ’s death as a propitiation (Rom 3:25) as in 1Jo 2:2.