There are several Psalms which speak of the whole heart. Consider what we can and must do with our whole heart.

PRAISE THE LORD
Psalm 9:1, I will praise thee, O Lord, with my whole heart; I will shew forth all thy marvelous works.
Psalm 111:1, Praise ye the Lord. I will praise the Lord with my whole heart, in the assembly of the upright, and in the congregation.
Psalm 138:1, I will praise thee with my whole heart before the gods will I sing praise unto thee

SEEK THE LORD
Psalm 119:2, Blessed are they that keep his testimonies, and that seek him with the whole heart.
Psalm 119:10, With my whole heart have I sought thee: O let me not wander from thy commandments.

COMMITMENT TO THE LORD
Psalm 119:34, Give me understanding, and I shall keep thy law; yea, I shall observe it iwth my whole heart.
Psalm 119:69, The proud have forged a lie against me: but I will keep thy precepts with my whole heart.
Psalm 119:145, I cried with my whole heart; hear me, O Lord; I will keep thy statutes.

PRAYER TO THE LORD
Psalm 119:58, I entreat thy favour with my whole heart: be merciful unto me according to thy word.