How do we apply the Hadith "Deeds are but by intentions" to the Hadith "Indeed, a servant may utter a word pleasing to Allah, not thinking much of it, but Allah raises him by it in ranks. And indeed, a servant may utter a word displeasing to Allah, not thinking much of it, but it casts him into Hell"?

The hadith "Deeds are only by intentions" indicates that the validity of deeds depends on the intention and its effect in transforming permissible acts into acts of devotion, and obedience into disobedience (like showing off). However, it does not transform disobedience into obedience. Disobedient acts do not change their intention; rather, a malicious intention may multiply their sin.

As for the hadith "Indeed, a servant may utter a word pleasing to Allah, not giving it much thought, by which Allah raises him many degrees...", it does not contradict the hadith about intentions. His saying "not giving it much thought" means not ascertaining or reflecting on its consequences, not lacking intention. Many scholars have interpreted this word as a word spoken in the presence of a ruler, either to please him in an act of disobedience, or to please Allah by repelling injustice or supporting the oppressed.