Matthew 26:6

Now when Jesus was in Bethany, in the house of Simon the leper, there came unto him a woman having an alabaster cruse of exceeding precious ointment, and she poured it upon his head, as he sat at meat.

Simon the leper refers to a Simon who had been cured of leprosy, not to one who was at that time stricken with that disease. Since Christ alone was able to cure that malady, this means that Christ had healed Simon, and probably out of gratitude, Simon held this dinner in his home for Jesus. The woman mentioned was Mary, the sister of Lazarus and Martha who were also present at that dinner. Lazarus was a guest, Martha as usual was helping with the serving, and Mary, also as usual, was blessed with a deeper insight into the spiritual realities of the occasion.

A. T. Robertson's clear word on this incident removes any chance of confusing it with a similar event recorded in Luke 7:36ff which occurred in the home of Simon the Pharisee. Robertson wrote:

This anointing has nothing in common with that given by Luke, except the fact of a woman anointing the Saviour's feet, and the name Simon, which was common. The former was in Galilee; this is at Bethany near Jerusalem. There the host despised the woman who anointed; here, her brother is one of the guests, and her sister an active attendant. There the woman was a sinner, a notoriously bad woman; here it is the devout Mary who "sat at the Lord's feet and heard his words," months before. There the host thought it strange that Jesus allowed her to touch him; here the disciples complained of the waste. There the Saviour gave assurance of forgiveness, here of perpetual and world-wide honor. Especially notice that here the woman who anoints is anticipating his speedy death and burial, of which at the former time he had never distinctly spoken. In view of all these differences, it is absurd to represent the two anointings as the same, and outrageous on such slender grounds to cast reproach on Mary of Bethany.[3]

John adds the information that Jesus' feet were also anointed, gives the monetary value of the ointment as 300 pence, and names the precious ointment as nard or spikenard. John also gave the name of the principal objector among the disciples as Judas, and mentions Mary's wiping his feet with her hair. His mention of the odor that filled the house (along with other special details) indicates that John also was among those present.