The first instance of foot washing in the Bible when the Lord appeared to Abraham in Mamre:
Genesis 18:1 And the LORD appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day;
Genesis 18:2 And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground,
Genesis 18:3 And said, My LORD, if now I have found favour in thy sight, pass not away, I pray thee, from thy servant:
Genesis 18:4 Let a little water, I pray you, be fetched, and wash your feet, and rest yourselves under the tree:
Genesis 18:5 And I will fetch a morsel of bread, and comfort ye your hearts; after that ye shall pass on: for therefore are ye come to your servant. And they said, So do, as thou hast said.
Angels came to warn Lot and Lot offered to wash their feet
​​Genesis 19:1 And there came two angels to Sodom at even; and Lot sat in the gate of Sodom: and Lot seeing them rose up to meet them; and he bowed himself with his face toward the ground;
Genesis 19:2 And he said, Behold now, my lords, turn in, I pray you, into your servant's house, and tarry all night, and wash your feet, and ye shall rise up early, and go on your ways. And they said, Nay; but we will abide in the street all night.
Genesis 19:3 And he pressed upon them greatly; and they turned in unto him, and entered into his house; and he made them a feast, and did bake unleavened bread, and they did eat.
Laban provided water to wash the servant of Abraham (who had been sent to find Abraham's son Isaac a wife) and the men who were with him as well.
Genesis 24:31 And he said, Come in, thou blessed of the LORD; wherefore standest thou without? for I have prepared the house, and room for the camels.
Genesis 24:32 And the man came into the house: and he ungirded his camels, and gave straw and provender for the camels, and water to wash his feet, and the men's feet that were with him.
Genesis 24:33 And there was set meat before him to eat: but he said, I will not eat, until I have told mine errand. And he said, Speak on.
Genesis 24:34 And he said, I am Abraham's servant.
Water was often provided for foot washing and food was typically offered to weary visitors and travelers.
Genesis 43:24 And the man brought the men into Joseph's house, and gave them water, and they washed their feet; and he gave their asses provender.
Genesis 43:25 And they made ready the present against Joseph came at noon: for they heard that they should eat bread there.
Judges 19:21 So he brought him into his house, and gave provender unto the asses: and they washed their feet, and did eat and drink.
I Samuel 25:41
II Samuel 11:8
Song of Solomon 5:3
Psalm 58:10
Luke 7:44
John 13:1-16
​I Timothy 5:10

Jesus washing his disciples feet is not only a humble example for us to follow but also has a symbolic meaning. When Jesus Christ walked the earth in human form He became a servant to people.He focused most of His energies on teaching the word of the Lord and healing people. He was a tireless and obedient son and servant who obeyed the Lord's commandments and sacrificed His life to save ours. 
He set an example that He expects us to follow and that example exhibits extreme servitude toward people. This may be hard for us to humble ourselves to this degree but do it we must.
Jesus was in the process of getting ready for Passover and He knew that the time was coming soon when He would sacrifice Himself to save us. He loved us enough to die for us. 
At Passover the devil had already put the thought to betray Jesus in Judas Iscariot's heart. When the Passover supper was over Jesus knew that God the Father had put everything in His hands and he was in complete control.
Jesus was fully aware that God had given Him full authority and He knew that He came from God and would return to God. 
Now before the feast of the Passover, when Jesus knew that his hour was come that he should depart out of this world unto the Father, having loved his own which were in the world, he loved them unto the end. John 13:1-21
And supper being ended, the devil having now put into the heart of Judas Iscariot, Simon's son, to betray him: John 13: 2
Jesus knowing that the Father had given all things ino his hands, and that he was come from God, and went to God; he riseth from supper, and laid aside his garments and took a towel, and girded himself. John 13:4
After that he poureth water into a basin, and began to wash the disciples feet, and to wipe them with the towel wherewith he was girded.  John 13:5
Then cometh he to Simon Peter; and Peter saith unto him, Lord, doest thou wash my feet? John 13:6
Jesus answered and said unto him, What I do thou knowest not now; but thou shalt know hereafter.  John 13:7
Peter saith unto him, Thou shalt never wash my feet, Jesus answered, If I wash thee not, thou hast no part with me. John 13:8
Simon says don't wash my feet-wash my head
Simon Peter saith unto him, Lord, not my feet only but also my hands and my head. John 13:9
Jesus saith to him, He that is washed needeth not save to wash his feet, but is clean every whit; and ye are clean, but not all. John 13:10
For he knew who should betray him; therefore said he, Ye are not all clean. John 13:11
So after he had washed their feet, and had taken his garments, and was set down again, he said unto them, 
Know ye what I have done to you? John 13: 12
Ye call me Master and Lord: and ye say well, for so I am. John13:13
If I then, your Lord and Master, have washed your feet; ye also ought to wash one another's feet. John 13:14
Jesus revealed the symbolic meaning of foot washing
Jesus sets an example for people to follow
For I have given you an example, that ye should do as I have done to you. John 13:15
The servant is not better than the master
Verily, verily, I say unto you. The servant is not greater than his lord; neither he that is servant greater than he that sent him. John 13:16  ​

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