These generous deeds don't save us. Jesus already did that. We should be like Him. It is more blessed to give than to receive. 39-40 contain two axioms, general truths understood everywhere.
Blind guides can only produce blind followers.
And, don't expect pupils to rise above the level of what they have been taught. You teach what you are. A serious student who has a competent teacher will also be competent. Like begets like. 6. Jesus is speaking about the hypocrite who is blind to his own great faults but picks at the little faults of others.