Jamieson, Fausset and Brown on 1 Timothy 6:19

19. Laying up in store--"therefrom (that is, by this means [Alford]; but Bengel makes the Greek "apo" mean laying apart against a future time), laying up for themselves as a treasure" [Alford] (Mt 6:19, 20). This is a treasure which we act wisely in laying up in store, whereas the wisest thing we can do with earthly treasures is "to distribute" them and give others a share of them (1Ti 6:18).

good foundation--(See on 1Ti 3:13; Lu 6:48; 1Co 3:11). The sure reversion of the future heavenly inheritance: earthly riches scattered in faith lay up in store a sure increase of heavenly riches. We gather by scattering (Pr 11:24; 13:7; Lu 16:9).

that ... eternal life--The oldest manuscripts and versions read, "that which is really life," its joys being solid and enduring (Psa 16:11). The life that now is cannot be called so, its goods being unsubstantial, and itself a vapor (Jas 4:14). "In order that ('with their feet so to speak on this foundation' [De Wette]) they may lay hold on that which is life indeed."