Can it appear as if Jesus' sermon on the mount teaches a works righteousness?
I just started reading through Matthew 5 in my 'quiet time. Grace is not mentioned, at least explicitly. We have a perfect standard in the law, and we should be striving and desiring to live by the commandments, but we as sinners will always fall woefully short, thus Jesus' atonement for our behalf.
It would have been nice for Matthew to make that point. I can see why those who teach some sort of work righteousness comes from. It is just incomplete but without a strong systematic approach I can see where it comes from.
1. Personally, I don't see where the Sermon on the Mount could be construed as advocating a "works righteousness".

Let's look at the Beatitudes as paradigmatic.
Matthew 5:3-12 (ASV) Blessed are the poor in spirit: for theirs is the kingdom of heaven. Blessed are they that mourn: for they shall be comforted. Blessed are the meek: for they shall inherit the earth. Blessed are they that hunger and thirst after righteousness: for they shall be filled. Blessed are the merciful: for they shall obtain mercy. Blessed are the pure in heart: for they shall see God. Blessed are the peacemakers: for they shall be called sons of God. Blessed are they that have been persecuted for righteousness' sake: for theirs is the kingdom of heaven. Blessed are ye when [men] shall reproach you, and persecute you, and say all manner of evil against you falsely, for my sake. Rejoice, and be exceeding glad: for great is your reward in heaven: for so persecuted they the prophets that were before you.
There is an unfortunate reading today of these beatitudes, specifically in regard to the word, "blessed", interpreting it to mean
happy. For example, I have heard/read often that this text should be read, "
Happy are the poor in spirit:...", meaning IF you are poor in spirit you
will be happy. On the contrary, the word
blessed is best interpreted and thus understood as meaning, "favored of God". Thus the text should be read as, "God looks with favor upon those who are poor in spirit..." The text is stating a present reality in regard to those who are poor in spirit, vs. a promise to those who somehow become poor in spirit.
2. Jesus is addressing, therefore, those who
have been given grace vs. those who will receive grace IF they do or become something. Grace is inseparably implied and the basis for all that Christ is teaching in Matthew 5-7 in such passages. Looking at the next chapter; 6 where Jesus deals with the matter of prayer, again grace underlies His teaching. For who can call God their "Father" other than those who have been made children of God by grace and who have repented of their sins and cast themselves upon the Lord Christ? (Jh 1:12,13)
3. Perhaps if you look at the Sermon on the Mount as an illustration or example of James 2:24,26 where works are
evidences of grace (faith) rather than works meriting grace.