Woe unto you, scribes and Pharisees, hypocrites! for ye are like unto whited sepulchres, which indeed appear beautiful outward, but are within full of dead men's bones, and of all uncleanness.

People's New Testament

23:27 For ye are like unto whitewashed sepulchres. It is stated that on the 15th of the month of Adair, before the Passover, the Jews whitewashed all the spots where graves were situated. This was done both to beautify them and to mark the spots as to prevent any one from passing over them, which would occasion Levitical defilement. For this practice, they cited Nu 19:16 Eze 39:15. This custom gave the basis for the Savior's figure. In plain view of the Savior and his hearers, as they stood in the temple court, could be seen the whitened tombs along the western slope of Olivet, some of which are still seen to this day.

Beautiful outward, but are within full of dead men's bones. A powerful figure to show forth the contrast between the sanctimonious professions of the Pharisees and their unholy lives.

Jamieson-Fausset-Brown Bible Commentary

27. Woe unto you, scribes and Pharisees, hypocrites! for ye are like whited sepulchres-or, whitewashed sepulchres. (Compare Ac 23:3). The process of whitewashing the sepulchres, as Lightfoot says, was performed on a certain day every year, not for ceremonial cleansing, but, as the following words seem rather to imply, to beautify them.

which indeed appear beautiful outward, but are within full of dead men's bones, and of all uncleanness-What a powerful way of conveying the charge, that with all their fair show their hearts were full of corruption! (Compare Ps 5:9; Ro 3:13). But our Lord, stripping off the figure, next holds up their iniquity in naked colors.

Wherefore ye be witnesses unto yourselves, that ye are the children of them which killed the prophets-that is, "ye be witnesses that ye have inherited, and voluntarily served yourselves heirs to, the truth-hating, prophet-killing, spirit of your fathers." Out of pretended respect and honor, they repaired and beautified the sepulchres of the prophets, and with whining hypocrisy said, "If we had been in their days, how differently should we have treated these prophets?" While all the time they were witnesses to themselves that they were the children of them that killed the prophets, convicting themselves daily of as exact a resemblance in spirit and character to the very classes over whose deeds they pretended to mourn, as child to parent. In Lu 11:44 our Lord gives another turn to this figure of a grave: "Ye are as graves which appear not, and the men that walk over them are not aware of them." As one might unconsciously walk over a grave concealed from view, and thus contract ceremonial defilement, so the plausible exterior of the Pharisees kept people from perceiving the pollution they contracted from coming in contact with such corrupt characters.

Matthew Henry's Concise Commentary

23:13-33 The scribes and Pharisees were enemies to the gospel of Christ, and therefore to the salvation of the souls of men. It is bad to keep away from Christ ourselves, but worse also to keep others from him. Yet it is no new thing for the show and form of godliness to be made a cloak to the greatest enormities. But dissembled piety will be reckoned double iniquity. They were very busy to turn souls to be of their party. Not for the glory of God and the good of souls, but that they might have the credit and advantage of making converts. Gain being their godliness, by a thousand devices they made religion give way to their worldly interests. They were very strict and precise in smaller matters of the law, but careless and loose in weightier matters. It is not the scrupling a little sin that Christ here reproves; if it be a sin, though but a gnat, it must be strained out; but the doing that, and then swallowing a camel, or, committing a greater sin. While they would seem to be godly, they were neither sober nor righteous. We are really, what we are inwardly. Outward motives may keep the outside clean, while the inside is filthy; but if the heart and spirit be made new, there will be newness of life; here we must begin with ourselves. The righteousness of the scribes and Pharisees was like the ornaments of a grave, or dressing up a dead body, only for show. The deceitfulness of sinners' hearts appears in that they go down the streams of the sins of their own day, while they fancy that they should have opposed the sins of former days. We sometimes think, if we had lived when Christ was upon earth, that we should not have despised and rejected him, as men then did; yet Christ in his Spirit, in his word, in his ministers, is still no better treated. And it is just with God to give those up to their hearts' lusts, who obstinately persist in gratifying them. Christ gives men their true characters.