There is none in the heavens and the earth but comes to the Most Beneficent as a slave. [Maryam 19:93]Islam forbade us from exceeding the proper bounds in this matter so that Tawhid may remain pure and clean, and so that deeds may be performed purely for Allah. Exaggerating the good qualities of people most definitely leads to associating partners with Allah.
In this regard, we have the example of the Christians, who continued to exaggerate the qualities of 'Iesa, peace be upon him, until they made him a god on one occasion, and the son of a god on another, and a part of a god on yet another occasion - all of which is disbelief itself. Allah Almighty says:
Surely, they have disbelieved who say: "Allah is the Mesiah, son of Maryam." [Al-Ma'idah 5:72]
Surely, disbelievers are those who said: "Allah is the third of the three." [Al-Ma'idah 5:73]They only deviated so far from the correct path because they exceeded the proper bounds regarding 'Iesa. Allah clarified that fact and made clear to them the way of the truth, saying:
O People of the Scripture (Jews and Christians)! Do not exceed the limits in your religion, nor say of Allah but the truth. [An-Nisa' 4:171]So that the Muslims are saved from what other nations have fallen into; the Prophet (SAW) said:
Do not praise me as the Christians praised the son of Maryam; indeed, I am only a slave, so say, "The slave of Allah and His Messenger." [Recorded by Al-Bukhari in the Book of the Prophets.]
Over-exaggerating the Righteous People Is The Basis For The Worship Of Idols
It has been related that the names of the idols that were worshiped are the names of righteous people; they had followers who would glorify them, and when they died, those followers said, "Let us erect statues where they used to gather so that we may continue to remember them." When that generation died and when much time passed, future generations came, not knowing the purpose of the statues; the Shaitan seduced them into believing that their fathers and grandfathers used to worship the statues, and so they began to do the same.
[Credit goes to 'What Must Be Known About Islam', a comprehensive book, compiled by Muhammad bin 'Ali Al-Arfaj, translated by Darussalam, global leaders in Islamic books.]