骨肉至亲 Of self's own flesh and blood

骨肉相连 Bones and flesh hold together

恩重如山 A great debt of gratitude

返哺之恩 Grace of returning to food of chewing

尊老慈幼 Respect the kind old child

百善孝为先 Filial piety is the most important of all virtues

老吾老以及人之老

Take care of own aged parents first and then extend the same care to the aged people in general

寸草春晖 A blade of grass to repay the spring brightness

承欢膝下 Please parents by living with them

安老怀少 Ampere of old bosom is few

Source: english.qianlong.com