As-Saaffaat 37:125

إِذْ قَالَ لِقَوْمِهِ أَلاَ تَتَّقُونَ

(When he said to his people: "Will you not have Taqwa") means, `do you not fear Allah when you worship others instead of Him'

أَتَدْعُونَ بَعْلاً وَتَذَرُونَ أَحْسَنَ الْخَـلِقِينَ

(Will you call upon Ba`l and forsake the Best of creators,) Ibn `Abbas, may Allah be pleased with him, Mujahid, `Ikrimah, Qatadah and As-Suddi said that the word Ba`l means lord. `Ikrimah and Qatadah said, "This is the language of the people of Yemen." According to another report from Qatadah, it is the language of Azd Shanu'ah. `Abdur-Rahman bin Zayd bin Aslam narrated from his father that it is the name of an idol which was worshipped by the people of a city called Ba`labak (Baalbek) which is to the west of Damascus. Ad-Dahhak said, "It is an idol which they used to worship."

أَتَدْعُونَ بَعْلاً

(Will you call upon Ba`l) means, `will you worship an idol,'

أَتَدْعُونَ بَعْلاً وَتَذَرُونَ أَحْسَنَ الْخَـلِقِينَ - اللَّهَ رَبَّكُمْ وَرَبَّ ءَابَآئِكُمُ الاٌّوَّلِينَ

(and forsake the Best of creators, Allah, your Lord and the Lord of your forefathers) means, `He is the One Who is deserving of your worship alone, with no partners or associates.'

فَكَذَّبُوهُ فَإِنَّهُمْ لَمُحْضَرُونَ

(But they denied him, so they will certainly be brought forth,) means, for the punishment on the Day of Reckoning.

إِلاَّ عِبَادَ اللَّهِ الْمُخْلَصِينَ

(Save the chosen servants of Allah.) means, those who believe in Him alone.

وَتَرَكْنَا عَلَيْهِ فِى الاٌّخِرِينَ

(And We left for him among the later generations.) means, he is praised and spoken of highly.

سَلَـمٌ عَلَى إِلْ يَاسِينَ

(Salam (peace!) be upon Ilyasin!) Similarly, one might say for Isma`il, Isma`in. This is the language (dialect) of Bani Asad; they say Mikal, Mika'il, and Mika'in. They say Ibrahim and Ibraham; Isra'il, Isra'in; Tur Sina', Tur Sinin. All of that is fine.

إِنَّا كَذَلِكَ نَجْزِى الْمُحْسِنِينَ - إِنَّهُ مِنْ عِبَادِنَا الْمُؤْمِنِينَ

(Verily, thus do We reward the doers of good. Verily, he was one of Our believing servants.) We have already discussed the meaning of this above. And Allah knows best.

Tafsir Ibn Kathir (abridged, English).