“What saved them was not divine favouritism, but the fact that they accepted by faith what the Lord said regarding the lamb and its shed blood. Salvation by faith in the promises of God.” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament
“Three words describing what is sought from God: blot out, wash thoroughly, cleanse: ‘blot out’ implies sin as a ‘black mark’ which God can see and which he can wipe away; ‘wash thoroughly’ is a ‘launderer’s’ verb, ingrained dirt requiring a detergent which can reach right down into the fibres (cf., Heb. 9: 14); ‘cleanse’ is mostly used in Leviticus (e.g., 13: 6) and deals with sin as a defilement which separates the sinner from the holy God.” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament
“Three words for what sin is: sin, iniquity, trans-gression. ‘Sin’ is the word for the specific offence (thought, word, deed, whatever). It is what we have in mind when we say ‘I’m sorry for that’; ‘iniquity’ derives from a verb meaning ‘to be bent’, and points to the inner defect or warp in human nature which is the well-spring of all sin; ‘transgression’ translates the serious word ‘rebellion’, as of a subordinate against an overlord (e.g., 2 Kgs. 3: 7).” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament
“My personal preference is to speak of ‘cumulative’ revelation. It would be possible to see the word ‘progressive’ as registering an advance from a ‘primitive’ to a ‘mature’ understanding, leaving the ‘primitive’ behind. This is not what happens in the Bible: hence the word ‘cumulative’ is preferable. Truth is built up layer upon layer, so that nothing is lost. The earlier statement is not primitive but partial— part of the complete whole that is yet to be.” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament
BTW NOTE: I don’t think Motyer is correct here. It’s not merely that layer is added to layer, nor that there is a cumulative build up of truth across Scripture. That overstates the unity of revelation. There is an age of types and shadows and there is an age of fulfillment. With the age of fulfillment, it’s not just that layers are added, but some things are taken away and replaced by other ideas.
“In the Old Testament, in God’s revelation though Moses, as in the New Testament, in the divine Covenant, the Law is not a ladder of merit we attempt to climb in order to win God’s favour; it is God’s pattern of holy living given to us because, by redemption, we are already in his favour. It is not a way of salvation by works of obedience; it is a pattern of obedience divinely provided for those who have been saved by grace.” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament
“Are you interpreting the ‘visual aid’? Egypt first, then Sinai; Passover first, then the giving of the Law; the divine work of grace first, then the life of responsive obedience, redemption/ salvation first, then walking with God in his appointed way of holiness.” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament
“Just as circumcision was the mark of grace in the Old Covenant, baptism is the mark of grace in the New Testament, the mark of God on those who are his. As Covenant signs, circumcision and baptism speak of the promises of God and symbolize the donation of those promises to authorised candidates, but, as promises, they only modulate into the spiritual realities of which they speak by the sovereign decision of God and the exercise of personal faith.” -Alec Motyer, A Christian’s Pocket Guide to Loving the Old Testament