Eli's sons refuse to obey God and steal meat from God's sacrifice. Comparatively we also see Isaac not resist being tied up by his father to be willingly laid on an altar before being saved by God. The important difference between Eli and Abraham as fathers was their willingness or unwillingness to tell their sons no.
Hannah a childless mother, vows to give her child to God for a life of service, if God will give her a son,which He does. Several years later we witmess God miraculously bless Hannah & her husband several times over because she faithfully kept her vow.