"But when they saw it, they all complained, saying, 'He has gone to be a guest with a man who is a sinner.' Then Zacchaeus stood and said to the Lord, 'Look, Lord, I give half of my goods to the poor; and if I have taken anything from anyone by false accusation, I restore fourfold.' And Jesus said to him, 'Today salvation has come to this house, because he also is a son of Abraham; for the Son of Man has come to seek and to save that which was lost.'"
Those who observed Jesus going to Zacchaeus' house "all complained" (with the exception of His closest disciples, presumably) - "He has gone to be a guest with a man who is a sinner." There is no evidence here that those who murmured against Jesus harbored any hatred against Him. It is likely that they just can't understand why He is associating with a man like Zacchaeus. Jesus' behavior here (and on many other occasions) was a disappointment to many who desired to make Him an earthly king. They wanted Him to behave like a king, and mingling with sinners (such as tax collectors) wasn't appropriate in their minds. They failed to comprehend that Jesus came to save sinners like Zacchaeus, and sinners like them!
"Look, Lord, I give half of my goods to the poor; and if I have taken anything from anyone by false accusation, I restore fourfold" (Luke 19:8). Based on Jesus' response in 19:9, it appears that these words were spoken in Zacchaeus' home. Additionally, it is most reasonable to interpret Zacchaeus' statement to mean that although he hadn't formerly been in the habit of giving half of his goods to the poor, immediately he would start doing such without delay. In Zacchaeus' case, the Mosaic law only required him to pay back 120%, not the 400% he pledged (cf. Lev. 6:1-5; Num. 5:7). Let it be observed that for Zacchaeus to propose to pay back fourfold to those whom he had cheated indicates that the vast majority of his wealth had been acquired honestly, otherwise such restitution would have been impossible.
Jesus declared - "Today salvation has come to this house." Zacchaeus was saved that day because of Jesus' visit and his own repentance. Although it is difficult for a rich man to be saved, it is not impossible with God's help (cf. Luke 18:18-30).
During Jesus' earthly ministry, His focus was upon the Hebrew people (i.e., "the lost sheep of the house of Israel"; Matt. 10:5,6; 15:24). Zacchaeus, though a social outcast, had Abraham as an ancestor, and thus, he was one of the "lost sheep" Jesus was sent to save. Let it be understood that although Jesus would not have went to Zacchaeus' house had he been a Gentile, the saving gospel message would soon be proclaimed to Jew and Gentile alike (cf. Matt. 28:19; Acts 10; Rom. 1:16).
"For the Son of Man has come to seek and to save that which was lost" (Luke 19:10). Jesus' fundamental purpose for His earthly ministry is here stated concisely. Stopping at Zacchaeus' house was entirely consistent with His purpose (as was continuing on toward Jerusalem; cf. 19:28).