[けいぞくはちからなり, keizokuhachikaranari](exp) persevering through something difficult makes one stronger; whatever doesn't kill us only makes us stronger; slow but steady wins the race[Add to Longdo]
[ちからがはいる, chikaragahairu](exp, v5r) (1) (See 力を入れる) to be filled with strength; to be filled with effort; to be under strain; to be under pressure; (2) to be enthusiastic about; (3) be tired (in sumo, ironic)[Add to Longdo]
[ちからをつける, chikarawotsukeru](exp, v1) (1) to build up one's strength; to get stronger; (2) to give (someone) strength; to cheer (someone) up; to encourage (someone)[Add to Longdo]