Matthew Poole and continuators on Genesis 35:4

4 And they gave unto Jacob all the strange gods which were in their hand, and all their earrings which were in their ears , and Jacob hid them under the Oak which was by Shechem.

Either because they had been abused to idolatry and superstition at Sichem or elsewhere, and therefore were to be destroyed according to Gods command now signified to Iacob and afterwards delivered to his posterity Deut. 7. 5. and 12. 3. or for fear they should be so abused. For the Scripture seems to insinuate, and other writers expresly affirm, that: divers heathen people did wear ear-rings for the honour of their idols and with the representations or ensigns of their idols engraven upon them. See Iudg. 8. 24.

After he had melted or broken them, which seems probable from parallel instances, as Exod. 32. 20. 2 King. 18. 4.

Under a certain oak, though not known to his family which it was. He chose that place, either as most proper to put monuments of Idolatry under those trees which were so much and so generally abused to Idolatry, as oaks especially were; Isa. 1. 29. or as the safest place, where they were likely to remain longest hid because the heathen had a veneration for Oaks, and therefore would not cut them down, nor dig them up, nor do any thing which had a tendency that way.

Marginal references: Jos. 24. 26. Judg. 9. 6.