Where the computation begins is not stated. The judges were given after the land's being given by lot, and that order of things reached up to Samuel, to four hundred and fifty years, whenever that four hundred and fifty years began. It might be at the Exodus, and very probably so. But it is not that there were judges during all that time. Indeed, they were only raised up occasionally. I have no difficulty myself as to the chronology, notwithstanding the dicta of some. The main blunder of their computations lies in this: they have taken Eli and Samson as distinct periods from the Philistine oppression, whereas it is perfectly clear the Philistine oppression included both. We have to go on to Mizpeh for the close.
'Mercies' and 'gracious one' (Hosios) are the same word, only singular and plural. It may, and sometimes does, mean 'holy,' but is not the regular word for it, which is Hagios: here it answers to chasid in Hebrew, which is contrasted in Ps. 89.19 with 'holy' (kadosh), which is applied to Jehovah (ver. 18). The beginning of the psalm speaks of the mercies (chasadim) or gracious ways of the Lord, and then in ver. 19 of that One in whom these graces or mercies are centred and conveyed, the Christ, to whom the apostle here applies it. The word chesed is generally 'grace' and 'loving-kindness' in God; chasid, 'pious,' 'gracious' applied to men, and 'merciful,' 'holy' to God: see Heb. 7.26.
The word translated 'worshipping,' 'worshippers,' and 'worshipped' at verses 43 and 50, also at chs. 16.14; 17.4 and 17, and 18.7, signified a numerous class of Gentiles who, acknowledging the vanity of idolatry and detesting its disorders, attended the Jewish worship.