( قَدْ خَسِرَ الَّذِينَ قَتَلُوا أَوْلَادَهُمْ سَفَهًا بِغَيْرِ عِلْمٍ ) (Those will have lost who killed their children in foolishness without knowledge): Those who killed their children out of ignorance, foolishness, and stupidity will suffer a great loss.

( وَحَرَّمُوا مَا رَزَقَهُمُ اللَّهُ افْتِرَاءً عَلَى اللَّهِ ) (and prohibited what Allah had provided for them, inventing untruth about Allah.): They prohibited many of the blessings which Allah (swt) bestowed upon them, such as children, animals, and crops, because of their invention of untruth and the lies they made about Allah (swt).

(قَدْ ضَلُّوا وَمَا كَانُوا مُهْتَدِينَ) (They have gone astray and were not [rightly] guided.): If these verses were said by a human, then saying (they have gone astray) would have been enough to deliver the meaning, and the phrase of (and were not rightly guided) would have been extra information. But since these are the words of Allah (swt), then there is a purpose behind them. Allah (swt) reinforces the notion that there is plenty of evidences that lead to guidance because Allah (swt) sent His Messengers (PBUT) to convey the truth, but despite all these signs, disbelievers made the wrong choice and went astray.